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Abdelwahed M, Benoit V, Maalej B, Hilbert P, Calemard LM, Kamoun H, Ammar-Keskes L, Belguith N. Genetic insights into fetal kidney development: Variants in HNF1A and PKHD1 genes. Gene 2024; 927:148625. [PMID: 38830515 DOI: 10.1016/j.gene.2024.148625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 05/22/2024] [Accepted: 05/29/2024] [Indexed: 06/05/2024]
Abstract
The orchestration of fetal kidney development involves the precise control of numerous genes, including HNF1A, HNF1B and PKHD1. Understanding the genetic factors influencing fetal kidney development is essential for unraveling the complexities of renal disorders. This study aimed to search for disease-causing variants in HNF1A, HNF1B, PKHD1 genes, among fetus and babies or via parental samples, using sanger sequencing, NGS technologie and MLPA. The study revealed an absence of gene deletions and disease-causing variants in the HNF1B gene. However, five previously SNPs in the HNF1A gene were identified in four patients (patients 1, 2, 3, and 4). These include c.51C > G (Exon1, p. Leu17=), c.79A > C (Exon1, p. Ile27Leu), c.1375C > T (Exon7, p. Leu459=), c.1460G > A (Exon7, p. Ser487Asn), and c.1501 + 7G > A (Intron7). Additionally, in addition to previously SNPs identified, a de novo heterozygous missense mutation (p.E508K) was detected in patient 4. Furthermore, a heterozygous mutation in exon 16 (p. Arg494*; c.1480C > T) was identified in both parents of patient 5, allowing predictions of fetal homozygosity. Bioinformatic analyses predicted the effects of the c.1522G > A mutation (p.E508K) on splicing processes, pre-mRNA structures, and protein instability and conformation. Similarly, the c.1480C > T mutation (p. Arg494*) was predicted to introduce a premature codon stop, leads to the production of a shorter protein with altered or impaired function. Identification of variants in the HNF1A and in PKHD1 genes provides valuable insights into the genetic landscape of renal abnormalities in affected patients. These findings underscore the heterogeneity of genetic variants contributing to renal disorders and emphasize the importance of genetic screening.
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Affiliation(s)
- Mayssa Abdelwahed
- Laboratory of Human Molecular Genetics, Faculty of Medecine of Sfax, University of Sfax, Tunisia.
| | - Valerie Benoit
- Center for Human Genetics, Institute of Pathology and Genetics, Gosselies, Belgium
| | - Bayen Maalej
- Pediatrics Emergency and of Resuscitation Department, HediChaker Hospital, Sfax, Tunisia
| | - Pascale Hilbert
- Center for Human Genetics, Institute of Pathology and Genetics, Gosselies, Belgium
| | - Laurence Michel Calemard
- LBMMS - Service Biochimie et Biologie Moléculaire - UM Dépistage néonatal, Biologie Foeto-maternelle et mucoviscidose, Centre de Biologie et Pathologie Est, CHU de Lyon HCL, France
| | - Hassen Kamoun
- Medical Genetics Department, HediChaker Hospital, Sfax, Tunisia
| | - Leila Ammar-Keskes
- Laboratory of Human Molecular Genetics, Faculty of Medecine of Sfax, University of Sfax, Tunisia
| | - Neila Belguith
- Laboratory of Human Molecular Genetics, Faculty of Medecine of Sfax, University of Sfax, Tunisia; Medical Genetics Department, HediChaker Hospital, Sfax, Tunisia
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Wang Y, Lilienfeldt N, Hekimi S. Understanding coenzyme Q. Physiol Rev 2024; 104:1533-1610. [PMID: 38722242 DOI: 10.1152/physrev.00040.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 04/08/2024] [Accepted: 05/01/2024] [Indexed: 08/11/2024] Open
Abstract
Coenzyme Q (CoQ), also known as ubiquinone, comprises a benzoquinone head group and a long isoprenoid side chain. It is thus extremely hydrophobic and resides in membranes. It is best known for its complex function as an electron transporter in the mitochondrial electron transport chain (ETC) but is also required for several other crucial cellular processes. In fact, CoQ appears to be central to the entire redox balance of the cell. Remarkably, its structure and therefore its properties have not changed from bacteria to vertebrates. In metazoans, it is synthesized in all cells and is found in most, and maybe all, biological membranes. CoQ is also known as a nutritional supplement, mostly because of its involvement with antioxidant defenses. However, whether there is any health benefit from oral consumption of CoQ is not well established. Here we review the function of CoQ as a redox-active molecule in the ETC and other enzymatic systems, its role as a prooxidant in reactive oxygen species generation, and its separate involvement in antioxidant mechanisms. We also review CoQ biosynthesis, which is particularly complex because of its extreme hydrophobicity, as well as the biological consequences of primary and secondary CoQ deficiency, including in human patients. Primary CoQ deficiency is a rare inborn condition due to mutation in CoQ biosynthetic genes. Secondary CoQ deficiency is much more common, as it accompanies a variety of pathological conditions, including mitochondrial disorders as well as aging. In this context, we discuss the importance, but also the great difficulty, of alleviating CoQ deficiency by CoQ supplementation.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Noah Lilienfeldt
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
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Elmubarak I, Shril S, Mansour B, Bao A, Kolvenbach CM, Kari JA, Shalaby MA, El Desoky S, Hildebrandt F, Schneider R. Recessive variants in MYO1C as a potential novel cause of proteinuric kidney disease. Pediatr Nephrol 2024; 39:2939-2945. [PMID: 38904753 DOI: 10.1007/s00467-024-06426-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/03/2024] [Accepted: 05/20/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome is the second leading cause of chronic kidney disease among patients < 25 years of age. Through exome sequencing, identification of > 65 monogenic causes has revealed insights into disease mechanisms of nephrotic syndrome (NS). METHODS To elucidate novel monogenic causes of NS, we combined homozygosity mapping with exome sequencing in a worldwide cohort of 1649 pediatric patients with NS. RESULTS We identified homozygous missense variants in MYO1C in two unrelated children with NS (c.292C > T, p.R98W; c.2273 A > T, p.K758M). We evaluated publicly available kidney single-cell RNA sequencing datasets and found MYO1C to be predominantly expressed in podocytes. We then performed structural modeling for the identified variants in PyMol using aligned shared regions from two available partial structures of MYO1C (4byf and 4r8g). In both structures, calmodulin, a common regulator of myosin activity, is shown to bind to the IQ motif. At both residue sites (K758; R98), there are ion-ion interactions stabilizing intradomain and ligand interactions: R98 binds to nearby D220 within the myosin motor domain and K758 binds to E14 on a calmodulin molecule. Variants of these charged residues to non-charged amino acids could ablate these ionic interactions, weakening protein structure and function establishing the impact of these variants. CONCLUSION We here identified recessive variants in MYO1C as a potential novel cause of NS in children.
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Affiliation(s)
- Izzeldin Elmubarak
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shirlee Shril
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bshara Mansour
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Aaron Bao
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Caroline M Kolvenbach
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Institute of Anatomy, Medical Faculty, University of Bonn, Bonn, Germany
| | - Jameela A Kari
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Mohamed A Shalaby
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Sherif El Desoky
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ronen Schneider
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
- Division of Nephrology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.
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Modi ZJ, Zhai Y, Yee J, Desmond H, Hao W, Sampson MG, Sethna CB, Wang CS, Gipson DS, Trachtman H, Kretzler M. Pediatric contributions and lessons learned from the NEPTUNE cohort study. Pediatr Nephrol 2024; 39:2555-2568. [PMID: 38233720 DOI: 10.1007/s00467-023-06256-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/20/2023] [Accepted: 12/05/2023] [Indexed: 01/19/2024]
Abstract
Primary glomerular diseases are rare entities. This has hampered efforts to better understand the underlying pathobiology and to develop novel safe and effective therapies. NEPTUNE is a rare disease network that is focused on patients of all ages with minimal change disease, focal segmental glomerulosclerosis, and membranous nephropathy. It is a longitudinal cohort study that collects detailed demographic, clinical, histopathologic, genomic, transcriptomic, and metabolomic data. The goal is to develop a molecular classification for these disorders that supersedes the traditional pathological features-based schema. Pediatric patients are important contributors to this ongoing project. In this review, we provide a snapshot of the children and adolescents enrolled in NEPTUNE and summarize some key observations that have been made based on the data accumulated during the study. In addition, we describe the development of NEPTUNE Match, a program that aims to leverage the multi-scalar information gathered for each individual patient to provide guidance about potential clinical trial participation based on the molecular characterization and non-invasive biomarker profile. This represents the first organized effort to apply principles of precision medicine to the treatment of patients with primary glomerular disease. NEPTUNE has proven to be an invaluable asset in the study of glomerular diseases in patients of all ages including children and adolescents.
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Affiliation(s)
- Zubin J Modi
- Division of Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
- Susan B. Meister Child Health Research and Evaluation Center, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Yan Zhai
- Division of Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Jennifer Yee
- Division of Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Hailey Desmond
- Division of Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Wei Hao
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Matthew G Sampson
- Division of Pediatric Nephrology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Kidney Disease Initiative and Medical Population Genetics Groups, Broad Institute, Cambridge, MA, USA
- Division of Kidney Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | | | - Chia-Shi Wang
- Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Debbie S Gipson
- Division of Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Howard Trachtman
- Division of Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA.
| | - Matthias Kretzler
- Department of Internal Medicine, Division of Nephrology, University of Michigan, Ann Arbor, MI, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
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Khare V, Cherqui S. Targeted gene therapy for rare genetic kidney diseases. Kidney Int 2024:S0085-2538(24)00631-8. [PMID: 39222842 DOI: 10.1016/j.kint.2024.07.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/13/2024] [Accepted: 07/01/2024] [Indexed: 09/04/2024]
Abstract
Chronic kidney disease (CKD) is one of the leading causes of mortality worldwide because of kidney failure and the associated challenges of its treatment including dialysis and kidney transplantation. About one-third of CKD cases are linked to inherited monogenic factors, making them suitable for potential gene therapy interventions. However, the intricate anatomical structure of the kidney poses a challenge, limiting the effectiveness of targeted gene delivery to the renal system. In this review, we explore the progress made in the field of targeted gene therapy approaches and their implications for rare genetic kidney disorders, examining preclinical studies and prospects for clinical application. In vivo gene therapy is most commonly used for kidney-targeted gene delivery and involves administering viral and non-viral vectors through various routes such as systemic, renal vein and renal arterial injections. Small nucleic acids have also been used in preclinical and clinical studies for treating certain kidney disorders. Unexpectedly, hematopoietic stem and progenitor cells have been used as an ex vivo gene therapy vehicle for kidney gene delivery, highlighting their ability to differentiate into macrophages within the kidney, forming tunneling nanotubes that can deliver genetic material and organelles to adjacent kidney cells, even across the basement membrane to target the proximal tubular cells. As gene therapy technologies continue to advance and our understanding of kidney biology deepens, there is hope for patients with genetic kidney disorders to eventually avoid kidney transplantation.
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Affiliation(s)
- Veenita Khare
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Stephanie Cherqui
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA.
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Tanzi A, Buono L, Grange C, Iampietro C, Brossa A, Arcolino FO, Arigoni M, Calogero R, Perin L, Deaglio S, Levtchenko E, Peruzzi L, Bussolati B. Urine-derived podocytes from steroid resistant nephrotic syndrome patients as a model for renal-progenitor derived extracellular vesicles effect and drug screening. J Transl Med 2024; 22:762. [PMID: 39143486 PMCID: PMC11323595 DOI: 10.1186/s12967-024-05575-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 08/04/2024] [Indexed: 08/16/2024] Open
Abstract
BACKGROUND Personalized disease models are crucial for evaluating how diseased cells respond to treatments, especially in case of innovative biological therapeutics. Extracellular vesicles (EVs), nanosized vesicles released by cells for intercellular communication, have gained therapeutic interest due to their ability to reprogram target cells. We here utilized urinary podocytes obtained from children affected by steroid-resistant nephrotic syndrome with characterized genetic mutations as a model to test the therapeutic potential of EVs derived from kidney progenitor cells (nKPCs). METHODS EVs were isolated from nKPCs derived from the urine of a preterm neonate. Three lines of urinary podocytes obtained from nephrotic patients' urine and a line of Alport syndrome patient podocytes were characterized and used to assess albumin permeability in response to nKPC-EVs or various drugs. RNA sequencing was conducted to identify commonly modulated pathways after nKPC-EV treatment. siRNA transfection was used to demonstrate the involvement of SUMO1 and SENP2 in the modulation of permeability. RESULTS Treatment with the nKPC-EVs significantly reduced permeability across all the steroid-resistant patients-derived and Alport syndrome-derived podocytes. At variance, podocytes appeared unresponsive to standard pharmacological treatments, with the exception of one line, in alignment with the patient's clinical response at 48 months. By RNA sequencing, only two genes were commonly upregulated in nKPC-EV-treated genetically altered podocytes: small ubiquitin-related modifier 1 (SUMO1) and Sentrin-specific protease 2 (SENP2). SUMO1 and SENP2 downregulation increased podocyte permeability confirming the role of the SUMOylation pathway. CONCLUSIONS nKPCs emerge as a promising non-invasive source of EVs with potential therapeutic effects on podocytes with genetic dysfunction, through modulation of SUMOylation, an important pathway for the stability of podocyte slit diaphragm proteins. Our findings also suggest the feasibility of developing a non-invasive in vitro model for screening regenerative compounds on patient-derived podocytes.
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Affiliation(s)
- Adele Tanzi
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, 10125, Italy
| | - Lola Buono
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, 10125, Italy
| | - Cristina Grange
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Corinne Iampietro
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, 10125, Italy
| | - Alessia Brossa
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, 10125, Italy
| | - Fanny Oliveira Arcolino
- Department of Pediatric Nephrology, Emma Children's Hospital, Amsterdam UMC, Amsterdam, The Netherlands
- Emma Centrum of Personalized Medicine, Emma Children's Hospital, Amsterdam UMC, Amsterdam, The Netherlands
| | - Maddalena Arigoni
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, 10125, Italy
| | - Raffaele Calogero
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, 10125, Italy
| | - Laura Perin
- Department of Urology, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Silvia Deaglio
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Elena Levtchenko
- Department of Pediatric Nephrology, Emma Children's Hospital, Amsterdam UMC, Amsterdam, The Netherlands
- Department of Development and Regeneration, Cluster Woman and Child, Laboratory of Pediatric Nephrology, KU Leuven, Leuven, Belgium
| | - Licia Peruzzi
- Pediatric Nephrology, ERKNet Center, Regina Margherita Children's Hospital, AOU Città della, Salute e della Scienza di Torino, Turin, Italy
| | - Benedetta Bussolati
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, Turin, 10125, Italy.
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7
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Platt CJ, Bierzynska A, Ding W, Saleem SA, Koziell A, Saleem MA. Rare heterozygous variants in paediatric steroid resistant nephrotic syndrome - a population-based analysis of their significance. Sci Rep 2024; 14:18568. [PMID: 39127776 DOI: 10.1038/s41598-024-68837-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 07/29/2024] [Indexed: 08/12/2024] Open
Abstract
Genetic testing in nephrotic syndrome may identify heterozygous predicted-pathogenic variants (HPPVs) in autosomal recessive (AR) genes that are known to cause disease in the homozygous or compound heterozygous state. In such cases, it can be difficult to define the variant's true significance and questions remain about whether a second pathogenic variant has been missed during analysis or whether the variant is an incidental finding. There are now known to be over 70 genes associated with nephrotic syndrome, the majority inherited as an AR trait. Knowledge of whether such HPPVs occur with equal frequency in patients compared to the general population would assist interpretation of their significance. Exome sequencing was performed on 187 Steroid-Resistant Nephrotic Syndrome (SRNS) paediatric patients recruited to a UK rare disease registry plus originating from clinics at Evelina, London. 59 AR podocytopathy linked genes were analysed in each patient and a list of HPPVs created. We compared the frequency of detected HPPVs with a 'control' population from the gnomAD database containing exome data from approximately 50,000 individuals. A bespoke filtering process was used for both patients and controls to predict 'likely pathogenicity' of variants. In total 130 Caucasian SRNS patients were screened across 59 AR genes and 201 rare heterozygous variants were identified. 17/201 (8.5%) were assigned as 'likely pathogenic' (HPPV) using our bespoke filtering method. Comparing each gene in turn, for SRNS patients with a confirmed genetic diagnosis, in 57 of the 59 genes we found no statistically significant difference in the frequency of these HPPVs between patients and controls (In genes ARHGDIA and TP53RK, we identified a significantly higher number of HPPVs in the control population compared with the patients when filtering was performed with 'high stringency' settings only). In the SRNS patients without a genetics diagnosis confirmed, there was no statistically significant difference identified in any gene between patient and control. In children with SRNS, we propose that identification of HPPV in AR podocytopathy linked genes is not necessarily representative of pathogenicity, given that the frequency is similar to that seen in controls for the majority. Whilst this may not exclude the presence of genetic kidney disease, this type of heterozygous variant is unlikely to be causal and each result must be interpreted in its clinical context.
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Affiliation(s)
- C J Platt
- Bristol Royal Hospital for Children, Bristol, BS2 8NJ, UK.
| | - A Bierzynska
- Bristol Renal, University of Bristol, Bristol, UK
| | - W Ding
- Bristol Renal, University of Bristol, Bristol, UK
| | | | - A Koziell
- King's College and Evelina, London, UK
| | - M A Saleem
- Bristol Renal, University of Bristol, Bristol, UK
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8
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Ichikawa Y, Sakakibara N, Nagano C, Inoki Y, Tanaka Y, Ueda C, Kitakado H, Kondo A, Ishimori S, Horinouchi T, Iijima K, Nozu K. In steroid-resistant nephrotic syndrome that meets the strict definition, monogenic variants are less common than expected. Pediatr Nephrol 2024:10.1007/s00467-024-06468-5. [PMID: 39093455 DOI: 10.1007/s00467-024-06468-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 07/06/2024] [Accepted: 07/09/2024] [Indexed: 08/04/2024]
Abstract
BACKGROUND In patients with steroid-resistant nephrotic syndrome (SRNS), the presence of monogenic variants influences therapeutic strategies. Large cohort studies reported the detection of monogenic variants in approximately 30% of patients with SRNS. However, these cohorts included many patients, such as those with symptomatic proteinuria, who did not meet the strict diagnostic criteria for pediatric nephrotic syndrome (NS). Therefore, we investigated the proportion of causative monogenic variants detected in patients who strictly met the diagnostic criteria of SRNS and explored their clinical characteristics. METHODS We examined pediatric SRNS cases with genetic analysis conducted in our hospital. Cases satisfying all of the following criteria were included: (1) age at onset 1-18 years, (2) serum albumin at onset ≤ 2.5 g/dl, (3) persistent heavy proteinuria, and (4) no complete remission after 4 weeks of steroid monotherapy. RESULTS The proportion of detected monogenic variants was 12% (22/185) among all patients. The proportion was only 7% (9/129) in patients with edema at disease onset compared with 38% (9/24) in those without (p < 0.0001). Monogenic variants were rare in patients with acute kidney injury associated with NS (1% (1/11)) or a history of complete remission (4% (2/51)). CONCLUSIONS Our study revealed a monogenic cause in 12% of individuals with strictly defined SRNS, a much smaller proportion than previously reported. The presence or absence of edema at the onset was an important factor to distinguish SRNS with monogenic cause from SRNS without. Our results provide further evidence of the SRNS types attributable to monogenic causes.
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Affiliation(s)
- Yuta Ichikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan.
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Yuta Inoki
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Yu Tanaka
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Chika Ueda
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Hideaki Kitakado
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Atsushi Kondo
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Shingo Ishimori
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
| | - Kazumoto Iijima
- Hyogo Prefectural Kobe Children's Hospital, Kobe, Japan
- Department of Advanced Pediatric Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
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9
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Schneider R, Mansour B, Kolvenbach CM, Buerger F, Salmanullah D, Lemberg K, Merz LM, Mertens ND, Saida K, Yousef K, Franken GAC, Bao A, Yu S, Hölzel S, Nicolas-Frank C, Steinsapir A, Goncalves KA, Shril S, Hildebrandt F. Phenotypic quantification of Nphs1-deficient mice. J Nephrol 2024:10.1007/s40620-024-01987-8. [PMID: 39003671 DOI: 10.1007/s40620-024-01987-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 05/06/2024] [Indexed: 07/15/2024]
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of chronic kidney disease in children and young adults. The most severe form of steroid-resistant nephrotic syndrome is congenital nephrotic syndrome Finnish type (CNSF), caused by biallelic loss-of-function variants in NPHS1, encoding nephrin. Since each of the 68 monogenic causes of steroid-resistant nephrotic syndrome represents a rare cause of the disease, tailoring therapeutic interventions to multiple molecular targets remains challenging, suggesting gene replacement therapy (GRT) as a viable alternative. To set the ground for a gene replacement study in vivo, we established rigorous, quantifiable, and reproducible phenotypic assessment of a conditional Nphs1 knockout mouse model. METHODS By breeding a floxed Nphs1fl/- mouse (Nphs1tm1Afrn/J) previously studied for pancreatic β-cell survival with a podocin promoter-driven Cre recombinase mouse model (Tg(NPHS2-Cre)295Lbh/J), we generated mice with podocyte-specific nephrin deficiency (Nphs1fl/fl NPHS2-Cre +). RESULTS We observed a median survival to postnatal day P5 in nephrin-deficient mice, whereas heterozygous control mice and wild type (WT) control group showed 90% and 100% survival, respectively (at P50 days). Light microscopy analysis showed a significantly higher number of renal-tubular microcysts per kidney section in nephrin-deficient mice compared to the control groups (P < 0.0022). Transmission electron microscopy demonstrated reduced foot process (FP) density in nephrin-deficient mice compared to controls (P < 0.0001). Additionally, proteinuria quantitation using urine albumin-to-creatinine ratio (UACR) was significantly higher in nephrin-deficient mice compared to controls. CONCLUSIONS This study represents the first comprehensive description of the kidney phenotype in a nephrin-deficient mouse model, laying the foundation for future gene replacement therapy endeavors.
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Affiliation(s)
- Ronen Schneider
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Bshara Mansour
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Caroline M Kolvenbach
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
- Institute of Anatomy and Cell Biology, Medical Faculty, University of Bonn, Bonn, Germany
| | - Florian Buerger
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Daanya Salmanullah
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Katharina Lemberg
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Lea M Merz
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
- Department of Pediatrics, University Leipzig, Leipzig, Germany
| | - Nils D Mertens
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Ken Saida
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Kirollos Yousef
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Gijs A C Franken
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Aaron Bao
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Seyoung Yu
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Selina Hölzel
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Camille Nicolas-Frank
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Andrew Steinsapir
- Deerfield Discovery and Development, Deerfield Management Company, L.P. (Series C), New York, USA
| | - Kevin A Goncalves
- Deerfield Discovery and Development, Deerfield Management Company, L.P. (Series C), New York, USA
| | - Shirlee Shril
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, USA.
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10
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Nagano C, Nozu K. A review of the genetic background in complicated WT1-related disorders. Clin Exp Nephrol 2024:10.1007/s10157-024-02539-x. [PMID: 39002031 DOI: 10.1007/s10157-024-02539-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 07/05/2024] [Indexed: 07/15/2024]
Abstract
The Wilms tumor 1 (WT1) gene was first identified in 1990 as a strong candidate for conferring a predisposition to Wilms tumor. The WT1 protein has four zinc finger structures (DNA binding domain) at the C-terminus, which bind to transcriptional regulatory sequences on DNA, and acts as a transcription factor. WT1 is expressed during kidney development and regulates differentiation, and is also expressed in glomerular epithelial cells after birth to maintain the structure of podocytes. WT1-related disorders are a group of conditions associated with an aberrant or absent copy of the WT1 gene. This group of conditions encompasses a wide phenotypic spectrum that includes Denys-Drash syndrome (DDS), Frasier syndrome (FS), Wilms-aniridia-genitourinary-mental retardation syndrome, and isolated manifestations of nephropathy or Wilms tumor. The genotype-phenotype correlation is becoming clearer: patients with missense variants in DNA binding sites including C2H2 sites manifest DDS and develop early-onset and rapidly developing end-stage kidney disease. A deeper understanding of the genotype-phenotype correlation has also been obtained in DDS, but no such correlation has been observed in FS. The incidence of Wilms tumor is higher in patients with DDS and exon-truncating variants than in those with non-truncating variants. Here, we briefly describe the genetic background of this highly complicated WT1-related disorders.
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Affiliation(s)
- China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan.
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-Cho, Chuo-Ku, Kobe, 650-0017, Japan
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11
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Moiseev SV, Shilov EM. [Kidney involvement in rare hereditary diseases]. TERAPEVT ARKH 2024; 96:559-564. [PMID: 39106495 DOI: 10.26442/00403660.2024.06.202722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 03/14/2024] [Indexed: 08/09/2024]
Abstract
Various rare inherited disorders can be associated with kidney involvement, including glomerulopathies, tubulopathies, multiple cysts, congenital anomalies of the kidneys and urinary tract, urolithiasis, malignant and benign tumors. Genetic nephropathy should be always considered in children, adolescents and young patients with the kidneys or urinary tract disorders and/or patients with positive family anamnesis. Extrarenal manifestations can be a valuable clue for diagnosis of certain hereditary diseases, e.g. neurosensory deafness in Alport syndrome or photofobia in nephropathic cystinosis. Diagnosis of monogenic inherited diseases should be verified by genetic testing. Specific drugs are available for treatment of certain hereditary diseases involving kidney, e.g. Fabry disease, cystinosis, primary hyperoxaluria I type and atypical hemolytic uremic syndrome.
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Affiliation(s)
- S V Moiseev
- Sechenov First Moscow State Medical University (Sechenov University)
- Lomonosov Moscow State University
| | - E M Shilov
- Sechenov First Moscow State Medical University (Sechenov University)
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12
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Caparali EB, De Gregorio V, Barua M. Genetic Causes of Nephrotic Syndrome and Focal and Segmental Glomerulosclerosis. ADVANCES IN KIDNEY DISEASE AND HEALTH 2024; 31:309-316. [PMID: 39084756 DOI: 10.1053/j.akdh.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 03/29/2024] [Accepted: 04/01/2024] [Indexed: 08/02/2024]
Abstract
The field of nephrology has a long-standing interest in deciphering the genetic basis of nephrotic syndrome (NS), motivated by the mechanistic insights it provides in chronic kidney disease. The initial era of genetic studies solidified NS and the focal segmental glomerulosclerosis lesion as podocyte disorders. The likelihood of identifying a single gene (called monogenic) cause is higher if certain factors are present such as positive family history. Obtaining a monogenic diagnosis enables reproductive counseling and screening of family members. Now, with a new era of genomic studies facilitated by technological advances and the emergence of large genetically characterized cohorts, more insights are apparent. This includes the phenotypic breadth associated with disease genes, as evidenced in Alport syndrome and congenital NS of the Finnish type. Moreover, the underlying genetic architecture is more complex than previously appreciated, as shown by genome-wide association studies, suggesting that variants in multiple genes collectively influence risk. Achieving molecularly informed diagnoses also holds substantial potential for personalizing medicine, including the development of targeted therapeutics. Illustrative examples include coenzyme Q10 for ADCK4-associated NS and inaxaplin, a small molecule that inhibits apolipoprotein L1 channel activity, though larger studies are required to confirm benefit.
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Affiliation(s)
- Emine Bilge Caparali
- Division of Nephrology, University Health Network, Toronto, Ontario, Canada; Division of Nephrology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Vanessa De Gregorio
- Division of Nephrology, University Health Network, Toronto, Ontario, Canada; Division of Nephrology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Moumita Barua
- Division of Nephrology, University Health Network, Toronto, Ontario, Canada; Division of Nephrology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
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13
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Mitrotti A, Giliberti M, Di Leo V, di Bari I, Pontrelli P, Gesualdo L. Hidden genetics behind glomerular scars: an opportunity to understand the heterogeneity of focal segmental glomerulosclerosis? Pediatr Nephrol 2024; 39:1685-1707. [PMID: 37728640 PMCID: PMC11026212 DOI: 10.1007/s00467-023-06046-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 05/02/2023] [Accepted: 05/30/2023] [Indexed: 09/21/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a complex disease which describes different kinds of kidney defects, not exclusively linked with podocyte defects. Since nephrin mutation was first described in association with early-onset nephrotic syndrome (NS), many advancements have been made in understanding genetic patterns associated with FSGS. New genetic causes of FSGS have been discovered, displaying unexpected genotypes, and recognizing possible site of damage. Many recent large-scale sequencing analyses on patients affected by idiopathic chronic kidney disease (CKD), kidney failure (KF) of unknown origin, or classified as FSGS, have revealed collagen alpha IV genes, as one of the most frequent sites of pathogenic mutations. Also, recent interest in complex and systemic lysosomal storage diseases, such as Fabry disease, has highlighted GLA mutations as possible causes of FSGS. Tubulointerstitial disease, recently classified by KDIGO based on genetic subtypes, when associated with UMOD variants, may phenotypically gain FSGS features, as well as ciliopathy genes or others, otherwise leading to completely different phenotypes, but found carrying pathogenic variants with associated FSGS phenotype. Thus, glomerulosclerosis may conceal different heterogeneous conditions. When a kidney biopsy is performed, the principal objective is to provide an accurate diagnosis. The broad spectrum of phenotypic expression and genetic complexity is demonstrating that a combined path of management needs to be applied. Genetic investigation should not be reserved only to selected cases, but rather part of medical management, integrating with clinical and renal pathology records. FSGS heterogeneity should be interpreted as an interesting opportunity to discover new pathways of CKD, requiring prompt genotype-phenotype correlation. In this review, we aim to highlight how FSGS represents a peculiar kidney condition, demanding multidisciplinary management, and in which genetic analysis may solve some otherwise unrevealed idiopathic cases. Unfortunately there is not a uniform correlation between specific mutations and FSGS morphological classes, as the same variants may be identified in familial cases or sporadic FSGS/NS or manifest a variable spectrum of the same disease. These non-specific features make diagnosis challenging. The complexity of FSGS genotypes requires new directions. Old morphological classification does not provide much information about the responsible cause of disease and misdiagnoses may expose patients to immunosuppressive therapy side effects, mistaken genetic counseling, and misguided kidney transplant programs.
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Affiliation(s)
- Adele Mitrotti
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy.
| | - Marica Giliberti
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Vincenzo Di Leo
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Ighli di Bari
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Paola Pontrelli
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Loreto Gesualdo
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
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14
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Campbell KN, Gesualdo L, Murphy E, Rheault MN, Srivastava T, Tesar V, Komers R, Trachtman H. Sparsentan for Focal Segmental Glomerulosclerosis in the DUET Open-Label Extension: Long-term Efficacy and Safety. Kidney Med 2024; 6:100833. [PMID: 38831932 PMCID: PMC11145552 DOI: 10.1016/j.xkme.2024.100833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Abstract
Rationale & Objective Sparsentan is a novel, non-immunosuppressive, single-molecule, dual endothelin angiotensin receptor antagonist (DEARA) examined in the ongoing phase 2 DUET trial for focal segmental glomerulosclerosis (FSGS). In the DUET 8-week double-blind period, sparsentan resulted in greater proteinuria reduction versus irbesartan. We report the long-term efficacy and safety of sparsentan during the open-label extension over more than 4 years. Study Design Patients were examined from their first sparsentan dose (double-blind period or open-label extension) through 4.6 years. Setting & Participants Patients with FSGS, excluding secondary FSGS. Intervention Sparsentan (200, 400, and 800 mg/d). Outcomes Urinary protein-creatinine ratio, FSGS partial remission endpoint (urinary protein-creatinine ratio ≤1.5 g/g and >40% reduction from baseline), estimated glomerular filtration rate, and blood pressure approximately every 12 weeks. Treatment-emergent adverse events by year and cases/100 patient-years. Results 109 patients were enrolled; 108 received ≥1 sparsentan dose; 103 entered the open-label extension (68 sparsentan, 35 irbesartan during the double-blind period). Sparsentan was ongoing in 45/108 patients (41.7%); median time to treatment discontinuation was 3.9 years (95% CI, 2.6-5.2). Mean percent proteinuria reduction from baseline was sustained through follow-up. Achieving partial remission within 9 months of first sparsentan dose (52.8% of patients) versus not achieving (47.2%) was associated with significantly slower rate of estimated glomerular filtration rate decline over the entire treatment period (-2.70 vs -6.56; P = 0.03) and in the first 2 years (-1.69 vs -6.46; P = 0.03). The most common treatment-emergent adverse events (>9 cases/100 patient-years) were headache, peripheral edema, upper respiratory infection, hyperkalemia, and hypotension. Peripheral edema and hypotension declined from year 1 (13.9% and 15.7% of patients, respectively) to ≤4% in years ≥2. There were no cases of heart failure and no patient deaths. Limitations The open-label extension does not include a comparison group. Conclusions Long-term sparsentan treatment showed sustained proteinuria reduction and a consistent safety profile.
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Affiliation(s)
| | | | | | | | | | - Vladimir Tesar
- Charles University, General University Hospital, Prague, Czech Republic
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15
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Bonilla M, Efe O, Selvaskandan H, Lerma EV, Wiegley N. A Review of Focal Segmental Glomerulosclerosis Classification With a Focus on Genetic Associations. Kidney Med 2024; 6:100826. [PMID: 38765809 PMCID: PMC11099322 DOI: 10.1016/j.xkme.2024.100826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) defines a distinct histologic pattern observed in kidney tissue that is linked to several distinct underlying causes, all converging on the common factor of podocyte injury. It presents a considerable challenge in terms of classification because of its varied underlying causes and the limited correlation between histopathology and clinical outcomes. Critically, precise nomenclature is key to describe and delineate the pathogenesis, subsequently guiding the selection of suitable and precision therapies. A proposed pathomechanism-based approach has been suggested for FSGS classification. This approach differentiates among primary, secondary, genetic, and undetermined causes, aiming to provide clarity. Genetic FSGS from monogenic mutations can emerge during childhood or adulthood, and it is advisable to conduct genetic testing in cases in which there is a family history of chronic kidney disease, nephrotic syndrome, or resistance to treatment. Genome-wide association studies have identified several genetic risk variants, such as those in apolipoprotein L1 (APOL1), that play a role in the development of FSGS. Currently, no specific treatments have been approved to treat genetic FSGS; however, interventions targeting underlying cofactor deficiencies have shown potential in some cases. Furthermore, encouraging results have emerged from a phase 2 trial investigating inaxaplin, a novel small molecule APOL1 channel inhibitor, in APOL1-associated FSGS.
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Affiliation(s)
- Marco Bonilla
- Section of Nephrology, Department of Medicine, University of Chicago, Chicago, IL
| | - Orhan Efe
- Division of Nephrology, Massachusetts General Hospital, Boston, MA
- Harvard Medical School, Boston, MA
| | - Haresh Selvaskandan
- IgA Mayer Nephropathy Laboratories, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- John Walls Renal Unit, University Hospitals of Leicester NHS Trust, Leicester, United Kingdom
| | - Edgar V. Lerma
- Section of Nephrology, University of Illinois at Chicago/Advocate Christ Medical Center, Oak Lawn, IL
| | - Nasim Wiegley
- University of California Davis School of Medicine, Division of Nephrology, Sacramento, CA
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16
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Tseng MH, Lin SH, Fan WL, Wu TW, Lin SP, Ding JJ, Tsai IJ, Tsai JD. Phenotype, genotype, and clinical outcome of Taiwanese with congenital nephrotic syndrome. J Formos Med Assoc 2024; 123:647-654. [PMID: 37845138 DOI: 10.1016/j.jfma.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/15/2023] [Accepted: 10/02/2023] [Indexed: 10/18/2023] Open
Abstract
BACKGROUND/PURPOSE Congenital nephrotic syndrome (CNS) is one of the important causes of end-stage kidney disease in children. Studies on the genotype, phenotype, and clinical outcome in infants with CNS caused by genetic mutations are scarce. METHODS We analyzed the genetic background, clinical manifestations, treatment response, and prognosis of pediatric patients with CNS in Taiwan. RESULTS Fifteen infants with CNS were enrolled, and 11 patients of median age 21 (interquartile range 3∼44) days caused by genetic mutations from 10 unrelated families were included in the study. Of the eleven patients, 9 had extra-renal manifestations including microcephaly, facial dysmorphism, and skeletal anomalies. More than two-thirds of the patients had disease onset before 1 month of age. Diffuse meningeal sclerosis was the most common histological characteristic. Whole exome sequencing followed by direct Sanger sequence revealed mutations in OSGEP (R247Q), WT1 (R366H and R467Q), LAMB2 (Q1209∗ and c. 5432-5451 19 bp deletion), NUP93 (D302V), and LAGE3 (c.188+1G > A). Three of the variants were novel. Corticosteroids and/or immunosuppressants were administered in 2 patients, but both were refractory to treatment. During the mean 3.5 years of follow-up, all but two died of uremia and sepsis. The two survivors reached end-stage kidney disease and required peritoneal dialysis, and one of them underwent uneventful renal transplantation. CONCLUSION The majority of patients with CNS in Taiwan were caused by OSGEP followed by WT1 mutation. R247Q is the hotspot mutation of OSGEP in Taiwan. CNS patients in Taiwan suffer from significant morbidity and mortality.
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Affiliation(s)
- Min-Hua Tseng
- Division of Nephrology, Department of Pediatrics, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Wen-Lang Fan
- Genomic Medicine Core Laboratory, Chang Gung Memorial Hospital, Kaohsiung, Taiwan
| | - Ta-Wei Wu
- Fetal and Neonatal Institute, Division of Neonatology, Children's Hospital Los Angeles, CA, USA; Department of Pediatrics, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
| | - Shuan-Pei Lin
- Division of Pediatric Genetics, Department of Pediatrics, MacKay Children's Hospital, Taipei, Taiwan
| | - Jhao-Jhuang Ding
- Department of Pediatrics, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - I-Jung Tsai
- Division of Nephrology, Department of Pediatrics, National Taiwan University Children's Hospital, Taipei, Taiwan.
| | - Jeng-Daw Tsai
- Division of Nephrology, Department of Pediatrics, MacKay Children's Hospital, Taipei, Taiwan; Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; Department of Pediatrics, Taipei Medical University Hospital, Taipei, Taiwan; Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
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17
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Oda K, Katayama K, Zang L, Toda M, Tanoue A, Saiki R, Yasuma T, D’Alessandro-Gabazza CN, Shimada Y, Mori M, Suzuki Y, Murata T, Hirai T, Tryggvason K, Gabazza EC, Dohi K. The Protective Role of KANK1 in Podocyte Injury. Int J Mol Sci 2024; 25:5808. [PMID: 38891998 PMCID: PMC11172089 DOI: 10.3390/ijms25115808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/21/2024] [Accepted: 05/25/2024] [Indexed: 06/21/2024] Open
Abstract
Approximately 30% of steroid-resistant nephrotic syndromes are attributed to monogenic disorders that involve 27 genes. Mutations in KANK family members have also been linked to nephrotic syndrome; however, the precise mechanism remains elusive. To investigate this, podocyte-specific Kank1 knockout mice were generated to examine phenotypic changes. In the initial assessment under normal conditions, Kank1 knockout mice showed no significant differences in the urinary albumin-creatinine ratio, blood urea nitrogen, serum creatinine levels, or histological features compared to controls. However, following kidney injury with adriamycin, podocyte-specific Kank1 knockout mice exhibited a significantly higher albumin-creatinine ratio and a significantly greater sclerotic index than control mice. Electron microscopy revealed more extensive foot process effacement in the knockout mice than in control mice. In addition, KANK1-deficient human podocytes showed increased detachment and apoptosis following adriamycin exposure. These findings suggest that KANK1 may play a protective role in mitigating podocyte damage under pathological conditions.
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Affiliation(s)
- Keiko Oda
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (K.O.); (A.T.); (R.S.); (M.M.); (Y.S.); (T.M.); (K.D.)
| | - Kan Katayama
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (K.O.); (A.T.); (R.S.); (M.M.); (Y.S.); (T.M.); (K.D.)
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden;
| | - Liqing Zang
- Graduate School of Regional Innovation Studies, Mie University, Tsu 514-8507, Mie, Japan;
| | - Masaaki Toda
- Department of Immunology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (M.T.); (T.Y.); (C.N.D.-G.); (E.C.G.)
| | - Akiko Tanoue
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (K.O.); (A.T.); (R.S.); (M.M.); (Y.S.); (T.M.); (K.D.)
| | - Ryosuke Saiki
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (K.O.); (A.T.); (R.S.); (M.M.); (Y.S.); (T.M.); (K.D.)
| | - Taro Yasuma
- Department of Immunology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (M.T.); (T.Y.); (C.N.D.-G.); (E.C.G.)
| | - Corina N. D’Alessandro-Gabazza
- Department of Immunology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (M.T.); (T.Y.); (C.N.D.-G.); (E.C.G.)
| | - Yasuhito Shimada
- Department of Integrative Pharmacology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan;
| | - Mutsuki Mori
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (K.O.); (A.T.); (R.S.); (M.M.); (Y.S.); (T.M.); (K.D.)
| | - Yasuo Suzuki
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (K.O.); (A.T.); (R.S.); (M.M.); (Y.S.); (T.M.); (K.D.)
| | - Tomohiro Murata
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (K.O.); (A.T.); (R.S.); (M.M.); (Y.S.); (T.M.); (K.D.)
| | - Toshinori Hirai
- Department of Pharmacy, Faculty of Medicine, Mie University Hospital, Tsu 514-8507, Mie, Japan;
| | - Karl Tryggvason
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, 171 77 Stockholm, Sweden;
| | - Esteban C. Gabazza
- Department of Immunology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (M.T.); (T.Y.); (C.N.D.-G.); (E.C.G.)
| | - Kaoru Dohi
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, Tsu 514-8507, Mie, Japan; (K.O.); (A.T.); (R.S.); (M.M.); (Y.S.); (T.M.); (K.D.)
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18
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Finn LS. Nephrotic Syndrome Throughout Childhood: Diagnosing Podocytopathies From the Womb to the Dorm. Pediatr Dev Pathol 2024:10935266241242669. [PMID: 38745407 DOI: 10.1177/10935266241242669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The etiologies of podocyte dysfunction that lead to pediatric nephrotic syndrome (NS) are vast and vary with age at presentation. The discovery of numerous novel genetic podocytopathies and the evolution of diagnostic technologies has transformed the investigation of steroid-resistant NS while simultaneously promoting the replacement of traditional morphology-based disease classifications with a mechanistic approach. Podocytopathies associated with primary and secondary steroid-resistant NS manifest as diffuse mesangial sclerosis, minimal change disease, focal segmental glomerulosclerosis, and collapsing glomerulopathy. Molecular testing, once an ancillary option, has become a vital component of the clinical investigation and when paired with kidney biopsy findings, provides data that can optimize treatment and prognosis. This review focuses on the causes including selected monogenic defects, clinical phenotypes, histopathologic findings, and age-appropriate differential diagnoses of nephrotic syndrome in the pediatric population with an emphasis on podocytopathies.
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Affiliation(s)
- Laura S Finn
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at The University of Pennsylvania, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
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19
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Liu PJ, Sayeeda K, Zhuang C, Krendel M. Roles of myosin 1e and the actin cytoskeleton in kidney functions and familial kidney disease. Cytoskeleton (Hoboken) 2024. [PMID: 38708443 DOI: 10.1002/cm.21861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/21/2024] [Accepted: 04/04/2024] [Indexed: 05/07/2024]
Abstract
Mammalian kidneys are responsible for removing metabolic waste and maintaining fluid and electrolyte homeostasis via selective filtration. One of the proteins closely linked to selective renal filtration is myosin 1e (Myo1e), an actin-dependent molecular motor found in the specialized kidney epithelial cells involved in the assembly and maintenance of the renal filter. Point mutations in the gene encoding Myo1e, MYO1E, have been linked to familial kidney disease, and Myo1e knockout in mice leads to the disruption of selective filtration. In this review, we discuss the role of the actin cytoskeleton in renal filtration, the known and hypothesized functions of Myo1e, and the possible explanations for the impact of MYO1E mutations on renal function.
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Affiliation(s)
- Pei-Ju Liu
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Kazi Sayeeda
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Cindy Zhuang
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Mira Krendel
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
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20
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Buerger F, Merz LM, Saida K, Yu S, Salmanullah D, Lemberg K, Mertens ND, Mansour B, Kolvenbach CM, Yousef K, Hölzel S, Braun A, Franken GAC, Goncalves KA, Steinsapir A, Endlich N, Schneider R, Shril S, Hildebrandt F. Quantitative phenotyping of Nphs1 knockout mice as a prerequisite for gene replacement studies. Am J Physiol Renal Physiol 2024; 326:F780-F791. [PMID: 38482553 PMCID: PMC11386980 DOI: 10.1152/ajprenal.00412.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/07/2024] [Accepted: 02/08/2024] [Indexed: 03/22/2024] Open
Abstract
Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of chronic kidney disease before the age of 25 yr. Nephrin, encoded by NPHS1, localizes to the slit diaphragm of glomerular podocytes and is the predominant structural component of the glomerular filtration barrier. Biallelic variants in NPHS1 can cause congenital nephrotic syndrome of the Finnish type, for which, to date, no causative therapy is available. Recently, adeno-associated virus (AAV) vectors targeting the glomerular podocyte have been assessed as a means for gene replacement therapy. Here, we established quantitative and reproducible phenotyping of a published, conditional Nphs1 knockout mouse model (Nphs1tm1.1Pgarg/J and Nphs2-Cre+) in preparation for a gene replacement study using AAV vectors. Nphs1 knockout mice (Nphs1fl/fl Nphs2-Cre+) exhibited 1) a median survival rate of 18 days (range: from 9 to 43 days; males: 16.5 days and females: 20 days); 2) an average foot process (FP) density of 1.0 FP/µm compared with 2.0 FP/µm in controls and a mean filtration slit density of 2.64 µm/µm2 compared with 4.36 µm/µm2 in controls; 3) a high number of proximal tubular microcysts; 4) the development of proteinuria within the first week of life as evidenced by urine albumin-to-creatinine ratios; and 5) significantly reduced levels of serum albumin and elevated blood urea nitrogen and creatinine levels. For none of these phenotypes, significant differences between sexes in Nphs1 knockout mice were observed. We quantitatively characterized five different phenotypic features of congenital nephrotic syndrome in Nphs1fl/fl Nphs2-Cre+ mice. Our results will facilitate future gene replacement therapy projects by allowing for sensitive detection of even subtle molecular effects.NEW & NOTEWORTHY To evaluate potential, even subtle molecular, therapeutic effects of gene replacement therapy (GRT) in a mouse model, prior rigorous quantifiable and reproducible disease phenotyping is necessary. Here, we, therefore, describe such a phenotyping effort in nephrin (Nphs1) knockout mice to establish the basis for GRT for congenital nephrotic syndrome. We believe that our findings set an important basis for upcoming/ongoing gene therapy approaches in the field of nephrology, especially for monogenic nephrotic syndrome.
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Affiliation(s)
- Florian Buerger
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Lea M Merz
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
- Department of Pediatrics, University Leipzig, Leipzig, Germany
| | - Ken Saida
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Seyoung Yu
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Daanya Salmanullah
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Katharina Lemberg
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Nils D Mertens
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Bshara Mansour
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Caroline M Kolvenbach
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
- Institute of Anatomy, Medical Faculty, University of Bonn, Bonn, Germany
| | - Kirollos Yousef
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Selina Hölzel
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Alina Braun
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Gijs A C Franken
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Kevin A Goncalves
- Deerfield Discovery and Development, Deerfield Management Company, L.P. (Series C), New York, New York, United States
| | - Andrew Steinsapir
- Deerfield Discovery and Development, Deerfield Management Company, L.P. (Series C), New York, New York, United States
| | | | - Ronen Schneider
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Shirlee Shril
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, United States
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21
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Cheng X, Chen J, Yang X, Chan H, Yang X, Jiao J, Wang A, Zhang G, Chen X, Li X, Wang M, Yang B, Yang H, Li Q. Comparison of different genetic testing modalities applied in paediatric patients with steroid-resistant nephrotic syndrome. Ital J Pediatr 2024; 50:85. [PMID: 38654395 DOI: 10.1186/s13052-024-01655-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 04/07/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) are monogenic in some cases, however, there are still no clear guidelines on genetic testing in the clinical practice of SRNS in children. METHODS Three hundred thirty-two children were diagnosed with SRNS, and all children underwent genetic testing, including gene panels and/or whole-exome/genome sequencing (WES/WGS), during treatment. We analysed the relationship between clinical manifestation and genotype, and compared different genetic testing methods' detection rates and prices. RESULTS In this study, 30.12% (100/332) of children diagnosed with SRNS had monogenic causes of the disease. With 33.7% (122/332) of children achieving complete remission, 88.5% (108/122) received steroids combined with tacrolimus (TAC). In detectability, WES increased by 8.69% (4/46) on gene panel testing, while WGS increased by 4.27% (5/117) on WES, and WES was approximately 1/7 of the price of WGS for every further 1% increase in pathogenicity. CONCLUSIONS We verified that steroids combined with TAC were the most effective option in paediatric SRNS. In detection efficiency, we found that WGS was the highest, followed by WES. The panel was the lowest, but the most cost-effective method when considering the economic-benefit ratio, and thus it should be recommended first in SRNS.
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Affiliation(s)
- Xueting Cheng
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Jiahuan Chen
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xueying Yang
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Han Chan
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xia Yang
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Jia Jiao
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Anshuo Wang
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Gaofu Zhang
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xuelan Chen
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoqin Li
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Mo Wang
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Baohui Yang
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Haiping Yang
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
| | - Qiu Li
- Department of Nephrology, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
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22
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Han Y, Sha H, Yang Y, Yu Z, Zhou L, Wang Y, Yang F, Qiu L, Zhang Y, Zhou J. Mutations in the NUP93, NUP107 and NUP160 genes cause steroid-resistant nephrotic syndrome in Chinese children. Ital J Pediatr 2024; 50:81. [PMID: 38650033 PMCID: PMC11036785 DOI: 10.1186/s13052-024-01656-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Accepted: 04/07/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND The variants of nucleoporins are extremely rare in hereditary steroid-resistant nephrotic syndrome (SRNS). Most of the patients carrying such variants progress to end stage kidney disease (ESKD) in their childhood. More clinical and genetic data from these patients are needed to characterize their genotype-phenotype relationships and elucidate the role of nucleoporins in SRNS. METHODS Four patients of SRNS carrying biallelic variants in the NUP93, NUP107 and NUP160 genes were presented. The clinical and molecular genetic characteristics of these patients were summarized, and relevant literature was reviewed. RESULTS All four patients in this study were female and initially presented with SRNS. The median age at the onset of the disease was 5.08 years, ranging from 1 to 10.5 years. Among the four patients, three progressed to ESKD at a median age of 7 years, ranging from 1.5 to 10.5 years, while one patient reached stage 3 chronic kidney disease (CKD3). Kidney biopsies revealed focal segmental glomerulosclerosis in three patients. Biallelic variants were detected in NUP93 in one patient, NUP107 in two patients, as well as NUP160 in one patient respectively. Among these variants, five yielded single amino acid substitutions, one led to nonsense mutation causing premature termination of NUP107 translation, one caused a single nucleotide deletion resulting in frameshift and truncation of NUP107. Furthermore, one splicing donor mutation was observed in NUP160. None of these variants had been reported previously. CONCLUSION This report indicates that biallelic variants in NUP93, NUP107 and NUP160 can cause severe early-onset SRNS, which rapidly progresses to ESKD. Moreover, these findings expand the spectrum of phenotypes and genotypes and highlight the importance of next-generation sequencing in elucidating the molecular basis of SRNS and allowing rational treatment for affected individuals.
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Affiliation(s)
- Yanxinli Han
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China
| | - Hongyu Sha
- Department of Pharmacy, Yantai Yuhuangding Hospital, Yantai, Shandong Province, 264000, China
| | - Yuan Yang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China
| | - Zhuowei Yu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China
| | - Lanqi Zhou
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China
| | - Yi Wang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China
| | - Fengjie Yang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China
| | - Liru Qiu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China
| | - Yu Zhang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China
| | - Jianhua Zhou
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei province, 430030, China.
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23
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Elmubarak I, Shril S, Mansour B, Bao A, Kolvenbach C, Desoky SE, Shalaby M, Kari J, Hildebrandt F, Schneider R. Recessive variants in MYO1C as a potential novel cause of proteinuric kidney disease. RESEARCH SQUARE 2024:rs.3.rs-4183332. [PMID: 38659911 PMCID: PMC11042399 DOI: 10.21203/rs.3.rs-4183332/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Background Steroid-resistant nephrotic syndrome is the second leading cause of chronic kidney disease among patients <25 years of age. Through whole exome sequencing, identification of >65 monogenic causes has rendered insights into disease mechanisms of nephrotic syndrome. Methods To elucidate novel monogenic causes of NS, we combined homozygosity mapping with ES in a worldwide cohort of 1649 pediatric patients with NS. Results We identified homozygous missense variants in MYO1C in two unrelated children with nephrotic syndrome (c.292C>T, p.R98W; c.2273 A>T, p.K758M). We evaluated publicly available kidney single-cell RNA sequencing datasets and found MYO1Cto be predominantly expressed in podocytes. We then performed structural modeling in molecular viewer PyMol using the super function aligning shared regions within both partial structures of MYO1C (4byf and 4r8g). In both structures, calmodulin, a common regulator of myosin activity, is shown to bind to the IQ motif. At both residue sites (K758; R98), there are ion-ion interactions stabilizing intradomain and ligand interactions: R98 binds to nearby D220 within the Myosin Motor Domain and K758 binds to E14 on a calmodulin molecule. Variants of these charged residues to non-charged amino acids could ablate these ionic interactions, weakening protein structure and function establishing the impact of these variants. Conclusion We here identified recessive variants in MYO1C as a potential novel cause of nephrotic syndrome in children.
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Affiliation(s)
| | - Shirlee Shril
- Boston Childrens Hospital: Boston Children's Hospital
| | | | - Aaron Bao
- Boston Childrens Hospital: Boston Children's Hospital
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24
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Kachmar J, Boyer O, Lipska-Ziętkiewicz B, Morinière V, Gribouval O, Heidet L, Balasz-Chmielewska I, Benetti E, Cloarec S, Csaicsich D, Decramer S, Gellermann J, Guigonis V, Hogan J, Bayazit AK, Melk A, Nigmatullina N, Oh J, Ozaltin F, Ranchin B, Tsimaratos M, Trautmann A, Antignac C, Schaefer F, Dorval G. Steroid-Resistant Nephrotic Syndrome due to NPHS2 Variants Is Not Associated With Posttransplant Recurrence. Kidney Int Rep 2024; 9:973-981. [PMID: 38765578 PMCID: PMC11101709 DOI: 10.1016/j.ekir.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/07/2023] [Accepted: 01/02/2024] [Indexed: 05/22/2024] Open
Abstract
Introduction Unlike idiopathic nephrotic syndrome (NS), hereditary podocytopathies are not expected to recur after kidney transplantation. However, some reports of posttransplant recurrence of NS in patients carrying variants in the NPHS2 gene have been described, notably with the p.Arg138Gln variant, which is more prevalent in Europe. The objective of this study was to assess the risk of recurrence after kidney transplantation in a large cohort of patients with biallelic NPHS2 pathogenic variants. Methods Since January 2010, 61 patients identified at Necker-Enfants Malades Hospital and 56 enrolled in the PodoNet Registry with biallelic variants in the NPHS2 gene were transplanted and were compared with 44 transplanted children with steroid-resistant NS (SRNS) without any identified pathogenic variant. Results Of the 117 patients, 23 carried the p.Arg138Gln variant in the homozygous state and 16 in the compound heterozygous state. The other 78 patients carried different variants in the homozygous (n = 44) or compound heterozygous state. Only 1 patient with NPHS2-related SRNS experienced posttransplant recurrence (median follow-up of cohort 8.5 years [2.5-15]). Conversely, 7 of 44 patients (16%) without any identified pathogenic variant recurred within a maximum of 7 days after transplantation (median follow-up 8.9 years [0.6-13.9]). Conclusion In this large cohort, the risk of patients with causative variants in the NPHS2 gene to develop NS recurrence after kidney transplantation was extremely low. This is coherent with the pathophysiology of intrinsic slit-diaphragm disease. These data are reassuring and should be considered when counselling patients, making living kidney donation, whether related or not, a safe choice.
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Affiliation(s)
- Jessica Kachmar
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
| | - Olivia Boyer
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
- Service de néphrologie pédiatrique Centre de Référence MARHEA, Hôpital Necker-Enfants Malades, Assistance publique, Hôpitaux de Paris (AP-HP), Paris, France
| | - Beata Lipska-Ziętkiewicz
- Centre for Rare Diseases and Clinical Genetics Unit, Medical University of Gdansk, Gdansk, Poland
| | - Vincent Morinière
- Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, Assistance publique, Hôpitaux de Paris (AP-HP), Paris, France
| | - Olivier Gribouval
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
| | - Laurence Heidet
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
- Service de néphrologie pédiatrique Centre de Référence MARHEA, Hôpital Necker-Enfants Malades, Assistance publique, Hôpitaux de Paris (AP-HP), Paris, France
| | - Irena Balasz-Chmielewska
- Department of Pediatrics, Nephrology and Hypertension, Medical University of Gdansk, Gdansk, Poland
| | - Elisa Benetti
- Pediatric Nephrology Unit, Padua University Hospital, Padua, Italy
| | - Sylvie Cloarec
- Service de Néphrologie-Hémodialyse pédiatrique, Centre de compétence Maladies Rénales Rares, CHRU Tours-Clocheville, Tours, France
| | - Dagmar Csaicsich
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Stéphane Decramer
- Pediatric Nephrology Unit, Toulouse University Hospital; Centre De Référence Des Maladies Rénales Rares du Sud-Ouest, SoRare; INSERM U1048, Institute of Cardiovascular and Metabolic Diseases, Toulouse, France
| | - Jutta Gellermann
- Klinik für Pädiatrie/Nephrologie, Charité Campus Virchox-Klinikum, Berlin, Germany
| | | | - Julien Hogan
- Pediatric Nephrology, Hôpital Universitaire Robert-Debré; Paris Translational Research Center for Organ Transplantation, Inserm UMR-S970, Université Paris Cité, Paris, France
| | | | - Anette Melk
- Children’s Hospital, Hannover Medical School, Hannover, Germany
| | - Nazym Nigmatullina
- National Research Center for Maternal and Child Heatlh, Astana, Kazakhstan
| | - Jun Oh
- Pediatric Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fatih Ozaltin
- Department of Pediatric Nephrology, Hacettepe University, Faculty of Medicine, Sihhiye, Ankara, Türkiye
| | - Bruno Ranchin
- Pediatric Nephrology Unit, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Université de Lyon, Lyon, France
| | - Michel Tsimaratos
- Faculté de médecine de Marseille, Université de la Méditerranée, Marseille, France
| | - Agnes Trautmann
- Department of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University of Heidelberg, Germany
| | - Corinne Antignac
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
| | - Franz Schaefer
- Department of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University of Heidelberg, Germany
| | - Guillaume Dorval
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
- Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, Assistance publique, Hôpitaux de Paris (AP-HP), Paris, France
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25
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Kovalik ME, Dacanay MA, Crowley SD, Hall G. Swollen Feet: Considering the Paradoxical Roles of Interleukins in Nephrotic Syndrome. Biomedicines 2024; 12:738. [PMID: 38672094 PMCID: PMC11048099 DOI: 10.3390/biomedicines12040738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/11/2024] [Accepted: 03/15/2024] [Indexed: 04/28/2024] Open
Abstract
Interleukins are a family of 40 bioactive peptides that act through cell surface receptors to induce a variety of intracellular responses. While interleukins are most commonly associated with destructive, pro-inflammatory signaling in cells, some also play a role in promoting cellular resilience and survival. This review will highlight recent evidence of the cytoprotective actions of the interleukin 1 receptor (IL-1R)- and common gamma chain receptor (IL-Rγc)-signaling cytokines in nephrotic syndrome (NS). NS results from the injury or loss of glomerular visceral epithelial cells (i.e., podocytes). Although the causes of podocyte dysfunction vary, it is clear that pro-inflammatory cytokines play a significant role in regulating the propagation, duration and severity of disease. Pro-inflammatory cytokines signaling through IL-1R and IL-Rγc have been shown to exert anti-apoptotic effects in podocytes through the phosphoinositol-3-kinase (PI-3K)/AKT pathway, highlighting the potential utility of IL-1R- and IL-Rγc-signaling interleukins for the treatment of podocytopathy in NS. The paradoxical role of interleukins as drivers and mitigators of podocyte injury is complex and ill-defined. Emerging evidence of the cytoprotective role of some interleukins in NS highlights the urgent need for a nuanced understanding of their pro-survival benefits and reveals their potential as podocyte-sparing therapeutics for NS.
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Affiliation(s)
- Maria E. Kovalik
- Division of Nephrology, Duke University, Durham, NC 27701, USA; (M.E.K.)
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27710, USA
| | - Monique A. Dacanay
- Division of Nephrology, Duke University, Durham, NC 27701, USA; (M.E.K.)
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27710, USA
| | - Steven D. Crowley
- Division of Nephrology, Duke University, Durham, NC 27701, USA; (M.E.K.)
| | - Gentzon Hall
- Division of Nephrology, Duke University, Durham, NC 27701, USA; (M.E.K.)
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27710, USA
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26
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Buerger F, Salmanullah D, Liang L, Gauntner V, Krueger K, Qi M, Sharma V, Rubin A, Ball D, Lemberg K, Saida K, Merz LM, Sever S, Issac B, Sun L, Guerrero-Castillo S, Gomez AC, McNulty MT, Sampson MG, Al-Hamed MH, Saleh MM, Shalaby M, Kari J, Fawcett JP, Hildebrandt F, Majmundar AJ. Recessive variants in the intergenic NOS1AP-C1orf226 locus cause monogenic kidney disease responsive to anti-proteinuric treatment. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.03.17.24303374. [PMID: 38562757 PMCID: PMC10984069 DOI: 10.1101/2024.03.17.24303374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
In genetic disease, an accurate expression landscape of disease genes and faithful animal models will enable precise genetic diagnoses and therapeutic discoveries, respectively. We previously discovered that variants in NOS1AP , encoding nitric oxide synthase 1 (NOS1) adaptor protein, cause monogenic nephrotic syndrome (NS). Here, we determined that an intergenic splice product of N OS1AP / Nos1ap and neighboring C1orf226/Gm7694 , which precludes NOS1 binding, is the predominant isoform in mammalian kidney transcriptional and proteomic data. Gm7694 -/- mice, whose allele exclusively disrupts the intergenic product, developed NS phenotypes. In two human NS subjects, we identified causative NOS1AP splice variants, including one predicted to abrogate intergenic splicing but initially misclassified as benign based on the canonical transcript. Finally, by modifying genetic background, we generated a faithful mouse model of NOS1AP -associated NS, which responded to anti-proteinuric treatment. This study highlights the importance of intergenic splicing and a potential treatment avenue in a mendelian disorder.
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27
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Pantel D, Mertens ND, Schneider R, Hölzel S, Kari JA, Desoky SE, Shalaby MA, Lim TY, Sanna-Cherchi S, Shril S, Hildebrandt F. Copy number variation analysis in 138 families with steroid-resistant nephrotic syndrome identifies causal homozygous deletions in PLCE1 and NPHS2 in two families. Pediatr Nephrol 2024; 39:455-461. [PMID: 37670083 PMCID: PMC10979458 DOI: 10.1007/s00467-023-06134-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 07/06/2023] [Accepted: 08/10/2023] [Indexed: 09/07/2023]
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) is the second most common cause of kidney failure in children and adults under the age of 20 years. Previously, we were able to detect by exome sequencing (ES) a known monogenic cause of SRNS in 25-30% of affected families. However, ES falls short of detecting copy number variants (CNV). Therefore, we hypothesized that causal CNVs could be detected in a large SRNS cohort. METHODS We performed genome-wide single nucleotide polymorphism (SNP)-based CNV analysis on a cohort of 138 SRNS families, in whom we previously did not identify a genetic cause through ES. We evaluated ES and CNV data for variants in 60 known SRNS genes and in 13 genes in which variants are known to cause a phenocopy of SRNS. We applied previously published, predefined criteria for CNV evaluation. RESULTS We detected a novel CNV in two genes in 2 out of 138 families (1.5%). The 9,673 bp homozygous deletion in PLCE1 and the 6,790 bp homozygous deletion in NPHS2 were confirmed across the breakpoints by PCR and Sanger sequencing. CONCLUSIONS We confirmed that CNV analysis can identify the genetic cause in SRNS families that remained unsolved after ES. Though the rate of detected CNVs is minor, CNV analysis can be used when there are no other genetic causes identified. Causative CNVs are less common in SRNS than in other monogenic kidney diseases, such as congenital anomalies of the kidneys and urinary tract, where the detection rate was 5.3%. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Dalia Pantel
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - Nils D Mertens
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Ronen Schneider
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Selina Hölzel
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Jameela A Kari
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Sherif El Desoky
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Mohamed A Shalaby
- Department of Pediatrics, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
- Pediatric Nephrology Center of Excellence, King Abdulaziz University Hospital, Jeddah, Saudi Arabia
| | - Tze Y Lim
- Division of Nephrology, Department of Medicine, Columbia University, New York, NY, USA
| | - Simone Sanna-Cherchi
- Division of Nephrology, Department of Medicine, Columbia University, New York, NY, USA
| | - Shirlee Shril
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA.
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Zhang L, Zhao F, Ding G, Chen Y, Zhao S, Chen Q, Sha Y, Che R, Huang S, Zheng B, Zhang A. Monogenic Causes Identified in 23.68% of Children with Steroid-Resistant Nephrotic Syndrome: A Single-Centre Study. KIDNEY DISEASES (BASEL, SWITZERLAND) 2024; 10:61-68. [PMID: 38322629 PMCID: PMC10843177 DOI: 10.1159/000534853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 10/22/2023] [Indexed: 02/08/2024]
Abstract
Introduction Steroid-resistant nephrotic syndrome (SRNS) is the second most common cause of end-stage kidney disease in children, mostly associated with focal segmental glomerulosclerosis (FSGS). Advances in genomic science have enabled the identification of causative variants in 20-30% of SRNS patients. Methods We used whole exome sequencing to explore the genetic causes of SRNS in children. Totally, 101 patients with SRNS and 13 patients with nephrotic proteinuria and FSGS were retrospectively enrolled in our hospital between 2018 and 2022. For the known monogenic causes analysis, we generated a known SRNS gene list of 71 genes through reviewing the OMIM database and literature. Results Causative variants were identified in 23.68% of our cohort, and the most frequently mutated genes in our cohort were WT1 (7/27), NPHS1 (3/27), ADCK4 (3/27), and ANLN (2/27). Five patients carried variants in phenocopy genes, including MYH9, MAFB, TTC21B, AGRN, and FAT4. The variant detection rate was the highest in the two subtype groups with congenital nephrotic syndrome and syndromic SRNS. In total, 68.75% of variants we identified were novel and have not been previously reported in the literature. Conclusion Comprehensive genetic analysis is key to realizing the clinical benefits of a genetic diagnosis. We suggest that all children with SRNS undergo genetic testing, especially those with early-onset and extrarenal phenotypes.
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Affiliation(s)
- Luyan Zhang
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Fei Zhao
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Guixia Ding
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Ying Chen
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Sanlong Zhao
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Qiuxia Chen
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Yugen Sha
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Ruochen Che
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Songming Huang
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Bixia Zheng
- Nanjing Key Laboratory of Pediatrics, Children’s Hospital of Nanjing Medical University, Nanjing, China
| | - Aihua Zhang
- Department of Nephrology, Children’s Hospital of Nanjing Medical University, Nanjing, China
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29
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Yang Q, Tang D, Gan C, Bai M, Song X, Jiang W, Li Q, Chen Y, Zhang A, Wang M. Novel variants in CRB2 targeting the malfunction of slit diaphragm related to focal segmental glomerulosclerosis. Pediatr Nephrol 2024; 39:149-165. [PMID: 37452832 DOI: 10.1007/s00467-023-06087-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 06/01/2023] [Accepted: 06/29/2023] [Indexed: 07/18/2023]
Abstract
BACKGROUND Focal segmental glomerulosclerosis (FSGS) is a leading cause of steroid-resistant nephrotic syndrome (SRNS) that predominantly affects the podocytes. While mutations in genes causing pediatric SRNS have enhanced our understanding of FSGS, the disease's etiology remains complex and poorly understood. METHODS Whole exome sequencing (WES) was performed on a 9-year-old girl with SRNS associated with FSGS (SRNS-FSGS). We analyzed the expression of CRB2, slit diaphragm (SD)-associated proteins, and sphingosine 1-phosphate receptor 1 (S1PR1) in the proband and CRB2 knock-down podocytes. RESULTS In this study, we identified two novel compound heterozygous mutations in the Crumbs homolog 2 (CRB2) gene (c.2905delinsGCCACCTCGCGCTGGCTG, p.T969Afs*179 and c.3268C > G, p.R1090G) in a family with early-onset SRNS-FSGS. Our findings demonstrate that these CRB2 abnormalities were the underlying cause of SRNS-FSGS. CRB2 defects led to the dysfunction of podocyte SD-related proteins, including podocin, nephrin, and zonula occludens-1 (ZO-1), by reducing the phosphorylation level of S1PR1. Interestingly, the podocytic cytoskeleton remained unaffected, as demonstrated by normal expression and localization of synaptopodin. Our study also revealed a secondary decrease in CRB2 expression in idiopathic FSGS patients, indicating that CRB2 mutations may cause FSGS through a previously unknown mechanism involving SD-related proteins. CONCLUSIONS Overall, our findings shed new light on the pathogenesis of SRNS-FSGS and revealed that the novel pathogenic mutations in CRB2 contribute to the development of FSGS through a previously unknown mechanism involving SD-related proteins. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Qing Yang
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Dan Tang
- Department of Pediatrics, The Third Hospital of Mianyang, Sichuan Mental Health Center, Mianyang, 621000, Sichuan, China
| | - Chun Gan
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Mi Bai
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Xiaomei Song
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Wei Jiang
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Qiu Li
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China
| | - Yaxi Chen
- Centre for Lipid Research & Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, the Second Affiliated Hospital, Chongqing Medical University, Chongqing, People's Republic of China
| | - Aihua Zhang
- Department of Nephrology, State Key Laboratory of Reproductive Medicine, Children's Hospital of Nanjing Medical University, 72 Guangzhou Road, Nanjing, 210008, China
| | - Mo Wang
- Pediatric Research Institute, Department of Nephrology Children's Hospital of Chongqing Medical University, National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing Key Laboratory of Child Infection and Immunity, Children's Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
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Gipson DS, Wang CS, Salmon E, Gbadegesin R, Naik A, Sanna-Cherchi S, Fornoni A, Kretzler M, Merscher S, Hoover P, Kidwell K, Saleem M, Riella L, Holzman L, Jackson A, Olabisi O, Cravedi P, Freedman BS, Himmelfarb J, Vivarelli M, Harder J, Klein J, Burke G, Rheault M, Spino C, Desmond HE, Trachtman H. FSGS Recurrence Collaboration: Report of a Symposium. GLOMERULAR DISEASES 2024; 4:1-10. [PMID: 38348154 PMCID: PMC10859699 DOI: 10.1159/000535138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/30/2023] [Indexed: 02/15/2024]
Affiliation(s)
- Debbie S. Gipson
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Chia-Shi Wang
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - Eloise Salmon
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Rasheed Gbadegesin
- Department of Medicine, Duke University, Durham, NC, USA
- Department of Pediatrics, Duke University, Durham, NC, USA
| | - Abhijit Naik
- Department of Medicine, University of Michigan, Ann Arbor, MI, USA
| | | | | | - Matthias Kretzler
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | | | - Paul Hoover
- Department of Medicine, Harvard University, Cambridge, MA, USA
| | - Kelley Kidwell
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Moin Saleem
- Translational Health Sciences, University of Bristol, Bristol, UK
| | - Leonardo Riella
- Department of Medicine, Harvard University, Cambridge, MA, USA
| | - Lawrence Holzman
- Department of Internal Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Paolo Cravedi
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | | - Marina Vivarelli
- Department of Pediatric Subspecialties, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Jennifer Harder
- Department of Internal Medicine, University of Louisville, Louisville, KY, USA
| | - Jon Klein
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - George Burke
- Department of Surgery, University of Miami, Miami, FL, USA
| | - Michelle Rheault
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Cathie Spino
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Hailey E. Desmond
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Howard Trachtman
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
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31
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Butt L, Unnersjö-Jess D, Reilly D, Hahnfeldt R, Rinschen MM, Bozek K, Schermer B, Benzing T, Höhne M. In vivo characterization of a podocyte-expressed short podocin isoform. BMC Nephrol 2023; 24:378. [PMID: 38114895 PMCID: PMC10731740 DOI: 10.1186/s12882-023-03420-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 12/01/2023] [Indexed: 12/21/2023] Open
Abstract
The most common genetic causes of steroid-resistant nephrotic syndrome (SRNS) are mutations in the NPHS2 gene, which encodes the cholesterol-binding, lipid-raft associated protein podocin. Mass spectrometry and cDNA sequencing revealed the existence of a second shorter isoform in the human kidney in addition to the well-studied canonical full-length protein. Distinct subcellular localization of the shorter isoform that lacks part of the conserved PHB domain suggested a physiological role. Here, we analyzed whether this protein can substitute for the canonical full-length protein. The short isoform of podocin is not found in other organisms except humans. We therefore analysed a mouse line expressing the equivalent podocin isoform (podocinΔexon5) by CRISPR/Cas-mediated genome editing. We characterized the phenotype of these mice expressing podocinΔexon5 and used targeted mass spectrometry and qPCR to compare protein and mRNA levels of podocinwildtype and podocinΔexon5. After immunolabeling slit diaphragm components, STED microscopy was applied to visualize alterations of the podocytes' foot process morphology.Mice homozygous for podocinΔexon5 were born heavily albuminuric and did not survive past the first 24 h after birth. Targeted mass spectrometry revealed massively decreased protein levels of podocinΔexon5, whereas mRNA abundance was not different from the canonical form of podocin. STED microscopy revealed the complete absence of podocin at the podocytes' slit diaphragm and severe morphological alterations of podocyte foot processes. Mice heterozygous for podocinΔexon5 were phenotypically and morphologically unaffected despite decreased podocin and nephrin protein levels.The murine equivalent to the human short isoform of podocin cannot stabilize the lipid-protein complex at the podocyte slit diaphragm. Reduction of podocin levels at the site of the slit diaphragm complex has a detrimental effect on podocyte function and morphology. It is associated with decreased protein abundance of nephrin, the central component of the filtration-slit forming slit diaphragm protein complex.
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Grants
- KFO 329, BR4917/3, INST 1856/71-1 FUGG Deutsche Forschungsgemeinschaft
- KFO 329, BR4917/3, INST 1856/71-1 FUGG Deutsche Forschungsgemeinschaft
- KFO 329, BR4917/3, INST 1856/71-1 FUGG Deutsche Forschungsgemeinschaft
- KFO 329, BR4917/3, INST 1856/71-1 FUGG Deutsche Forschungsgemeinschaft
- KFO 329, BR4917/3, INST 1856/71-1 FUGG Deutsche Forschungsgemeinschaft
- Project No: 2019_KollegSE.04 Else Kröner-Fresenius-Stiftung,Germany
- Project No: 2019_KollegSE.04 Eva Luise und Horst Köhler Stiftung
- NNF19OC0056043 Novo Nordisk Fonden
- Young Researcher Fellowship Carlsbergfondet
- 311-8.03.03.02-147635 North Rhine-Westphalia return program
- 01ZX1917B Bundesministerium für Bildung und Forschung
- BMBF 01-GM1901E Bundesministerium für Bildung und Forschung
- Universitätsklinikum Köln (8977)
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Affiliation(s)
- Linus Butt
- Department II of Internal Medicine, University Hospital Cologne CECAD building Joseph-Stelzmann-Str. 62, Cologne, 50931, Germany
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine, University of Cologne, University Hospital Cologne, CECAD Building, Joseph-Stelzmann-Str. 62, 50931, Cologne, Germany
- Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), Faculty of Medicine, University of Cologne, University Hospital Cologne, Cologne, Germany
| | - David Unnersjö-Jess
- Department II of Internal Medicine, University Hospital Cologne CECAD building Joseph-Stelzmann-Str. 62, Cologne, 50931, Germany
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine, University of Cologne, University Hospital Cologne, CECAD Building, Joseph-Stelzmann-Str. 62, 50931, Cologne, Germany
- MedTechLabs, Karolinska University Hospital, Solna, Sweden
| | - Dervla Reilly
- Department II of Internal Medicine, University Hospital Cologne CECAD building Joseph-Stelzmann-Str. 62, Cologne, 50931, Germany
| | - Robert Hahnfeldt
- Department II of Internal Medicine, University Hospital Cologne CECAD building Joseph-Stelzmann-Str. 62, Cologne, 50931, Germany
| | - Markus M Rinschen
- Department of Biomedicine and Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark
- Department of Medicine III, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katarzyna Bozek
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine, University of Cologne, University Hospital Cologne, CECAD Building, Joseph-Stelzmann-Str. 62, 50931, Cologne, Germany
| | - Bernhard Schermer
- Department II of Internal Medicine, University Hospital Cologne CECAD building Joseph-Stelzmann-Str. 62, Cologne, 50931, Germany
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine, University of Cologne, University Hospital Cologne, CECAD Building, Joseph-Stelzmann-Str. 62, 50931, Cologne, Germany
- Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), Faculty of Medicine, University of Cologne, University Hospital Cologne, Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine, University Hospital Cologne CECAD building Joseph-Stelzmann-Str. 62, Cologne, 50931, Germany
- Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine, University of Cologne, University Hospital Cologne, CECAD Building, Joseph-Stelzmann-Str. 62, 50931, Cologne, Germany
- Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), Faculty of Medicine, University of Cologne, University Hospital Cologne, Cologne, Germany
| | - Martin Höhne
- Department II of Internal Medicine, University Hospital Cologne CECAD building Joseph-Stelzmann-Str. 62, Cologne, 50931, Germany.
- Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), Faculty of Medicine, University of Cologne, University Hospital Cologne, Cologne, Germany.
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Thomasová D, Zelinová M, Libik M, Geryk J, Votýpka P, Rajnochová Bloudíčková S, Krejčí K, Reiterová J, Jančová E, Machová J, Kollárová M, Rychík I, Havrda M, Horáčková M, Putzová M, Šafránek R, Kollár M, Macek M. The most common founder pathogenic variant c.868G > A (p.Val290Met) in the NPHS2 gene in a representative adult Czech cohort with focal segmental glomerulosclerosis is associated with a milder disease and its underdiagnosis in childhood. Front Med (Lausanne) 2023; 10:1320054. [PMID: 38170106 PMCID: PMC10759319 DOI: 10.3389/fmed.2023.1320054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/24/2023] [Indexed: 01/05/2024] Open
Abstract
Background Genetic focal segmental glomerulosclerosis (FSGS) is caused by pathogenic variants in a broad spectrum of genes that have a variable representation based on subjects' ethnicity and/or age. The most frequently mutated autosomal recessive gene in FSGS is NPHS2. In this study, we analyzed the spectrum of NPHS2 variants and their associated phenotype in Czech adult FSGS patients. Methods A representative cohort of 234 adult patients with FSGS, derived from 225 families originating from all regions of Czechia, was analyzed by massively parallel sequencing. In this study, we focused on the comprehensive analysis of the NPHS2 gene. The histological classification of FSGS followed the Columbia classification. Results We detected seven (3%) cases bearing homozygous or compound heterozygous pathogenic NPHS2 variants. A single pathogenic variant c.868G > A (p.Val290Met) was found in the majority of NPHS2-positive cases (86%; 6 out of 7) in histologically confirmed instances of FSGS. Its allele frequency among unrelated NPHS2-associated FSGS patients was 50% (6/12), and Haplotype analysis predicted its origin to be a result of a founder effect. There is an identical V290M-related haplotype on all V290M alleles spanning a 0,7 Mb region flanking NPHS2 in Central European FSGS populations. The phenotype of the p.Val290Met NPHS2-associated FSGS demonstrated a later onset and a much milder course of the disease compared to other NPHS2 pathogenic variants associated with FSGS. The mean age of the FSGS diagnosis based on kidney biopsy evaluation was 31.2 ± 7.46 years. In 50% of all cases, the initial disease manifestation of proteinuria occurred only in adulthood, with 83% of these cases not presenting with edemas. One-third (33%) of the studied subjects progressed to ESRD (2 out of 6) at the mean age of 35.0 ± 2.82 years. Conclusions We identified the most prevalent pathogenic variant, p.Val290Met, in the NPHS2 gene among Czech adult FSGS patients, which has arisen due to a founder effect in Central Europe. The documented milder course of the disease associated with this variant leads to the underdiagnosis in childhood. We established the histopathological features of the NPHS2-associated adult FSGS cases based on the Columbia classification. This might improve patient stratification and optimize their treatment.
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Affiliation(s)
- Dana Thomasová
- Institute of Biology and Medical Genetics, University Hospital Motol and 2nd Faculty of Medicine, Charles University Prague, Prague, Czechia
| | - Michaela Zelinová
- Institute of Biology and Medical Genetics, University Hospital Motol and 2nd Faculty of Medicine, Charles University Prague, Prague, Czechia
| | - Malgorzata Libik
- Institute of Biology and Medical Genetics, University Hospital Motol and 2nd Faculty of Medicine, Charles University Prague, Prague, Czechia
| | - Jan Geryk
- Institute of Biology and Medical Genetics, University Hospital Motol and 2nd Faculty of Medicine, Charles University Prague, Prague, Czechia
| | - Pavel Votýpka
- Institute of Biology and Medical Genetics, University Hospital Motol and 2nd Faculty of Medicine, Charles University Prague, Prague, Czechia
| | | | - Karel Krejčí
- 3rd Department of Internal Medicine-Nephrology, Rheumatology and Endocrinology, University Hospital and Faculty of Medicine Palacký University Olomouc, Olomouc, Czechia
| | - Jana Reiterová
- Department of Nephrology, General University Hospital in Prague, First Faculty of Medicine, Charles University, Prague, Czechia
| | - Eva Jančová
- Department of Nephrology, General University Hospital in Prague, First Faculty of Medicine, Charles University, Prague, Czechia
| | - Jana Machová
- Department of Internal Medicine I, Faculty of Medicine in Pilsen, Charles University and Teaching Hospital, Pilsen, Czechia
- Biomedical Centre, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czechia
| | - Martina Kollárová
- Department of Internal Medicine, University Hospital Vinohrady and Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Ivan Rychík
- Department of Internal Medicine, University Hospital Vinohrady and Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Martin Havrda
- Department of Internal Medicine, University Hospital Vinohrady and Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Miroslava Horáčková
- Department of Internal Medicine, University Hospital Motol and 2nd Faculty of Medicine, Charles University, Prague, Czechia
| | - Martina Putzová
- Biopticka Laboratory, Pilsen, Czechia
- Faculty of Medicine in Plzeň - Charles University, Pilsen, Czechia
| | - Roman Šafránek
- Department of Nephrology, University Hospital Hradec Králové, Faculty of Medicine in Hradec Králové, Charles University, Hradec Králové, Czechia
| | - Marek Kollár
- Department of Pathology, Institute for Clinical and Experimental Medicine, Prague, Czechia
| | - Milan Macek
- Institute of Biology and Medical Genetics, University Hospital Motol and 2nd Faculty of Medicine, Charles University Prague, Prague, Czechia
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Yang G, Mack H, Harraka P, Colville D, Savige J. Ocular manifestations of the genetic renal tubulopathies. Ophthalmic Genet 2023; 44:515-529. [PMID: 37702059 DOI: 10.1080/13816810.2023.2253901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 08/26/2023] [Indexed: 09/14/2023]
Abstract
BACKGROUND The genetic tubulopathies are rare and heterogenous disorders that are often difficult to identify. This study examined the tubulopathy-causing genes for ocular associations that suggested their genetic basis and, in some cases, the affected gene. METHODS Sixty-seven genes from the Genomics England renal tubulopathy panel were reviewed for ocular features, and for retinal expression in the Human Protein Atlas and an ocular phenotype in mouse models in the Mouse Genome Informatics database. The genes resulted in disease affecting the proximal tubules (n = 24); the thick ascending limb of the loop of Henle (n = 10); the distal convoluted tubule (n = 15); or the collecting duct (n = 18). RESULTS Twenty-five of the tubulopathy-associated genes (37%) had ocular features reported in human disease, 49 (73%) were expressed in the retina, although often at low levels, and 16 (24%) of the corresponding mouse models had an ocular phenotype. Ocular abnormalities were more common in genes affected in the proximal tubulopathies (17/24, 71%) than elsewhere (7/43, 16%). They included structural features (coloboma, microphthalmia); refractive errors (myopia, astigmatism); crystal deposition (in oxalosis, cystinosis) and sclerochoroidal calcification (in Bartter, Gitelman syndromes). Retinal atrophy was common in the mitochondrial-associated tubulopathies. Structural abnormalities and crystal deposition were present from childhood, but sclerochoroidal calcification typically occurred after middle age. CONCLUSIONS Ocular abnormalities are uncommon in the genetic tubulopathies but may be helpful in recognizing the underlying genetic disease. The retinal expression and mouse phenotype data suggest that further ocular associations may become apparent with additional reports. Early identification may be necessary to monitor and treat visual complications.
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Affiliation(s)
- GeFei Yang
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
| | - Heather Mack
- Department of Surgery (Ophthalmology), The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Philip Harraka
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
| | - Deb Colville
- Department of Surgery (Ophthalmology), The University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Parkville, Australia
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Lin L, Ye Y, Fu H, Gu W, Zhao M, Sun J, Cao Z, Huang G, Xie Y, Liu F, Li L, Li Q, Mao J, Hu L. Effects of a novel ANLN E841K mutation associated with SRNS on podocytes and its mechanism. Cell Commun Signal 2023; 21:324. [PMID: 37957688 PMCID: PMC10644598 DOI: 10.1186/s12964-023-01218-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 07/09/2023] [Indexed: 11/15/2023] Open
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) is characterized by unrelieved proteinuria after an initial 4-8 weeks of glucocorticoid therapy. Genes in podocytes play an important role in causing SRNS. OBJECTIVE This study aimed to report a pathogenic mutation in SRNS patients and investigate its effects on podocytes, as well as the pathogenic mechanism. METHODS We screened out a novel mutation by using whole-exon sequencing in the SRNS cohort and verified it via Sanger sequencing. Conservative analysis and bioinformatic analysis were used to predict the pathogenicity of the mutation. In vitro, stable podocyte cell lines were constructed to detect the effect of the mutation on the function of the podocyte. Moreover, an in vivo mouse model of podocyte ANLN gene knockout (ANLNpodKO) was used to confirm clinical manifestations. Transcriptome analysis was performed to identify differential gene expression and related signaling pathways. RESULTS ANLN E841K was screened from three unrelated families. ANLN E841K occurred in the functional domain and was predicted to be harmful. The pathological type of A-II-1 renal biopsy was minimal change disease, and the expression of ANLN was decreased. Cells in the mutation group showed disordered cytoskeleton, faster cell migration, decreased adhesion, increased endocytosis, slower proliferation, increased apoptosis, and weakened interaction with CD2 association protein. ANLNpodKO mice exhibited more obvious proteinuria, more severe mesangial proliferation, glomerular atrophy, foot process fusion, and increased tissue apoptosis levels than ANLNflox/flox mice after tail vein injection of adriamycin. Upregulated differentially expressed genes in cells of the mutation group were mainly enriched in the PI3K-AKT pathway. CONCLUSION The novel mutation known as ANLN E841K affected the function of the ANLN protein by activating the PI3K/AKT/mTOR/apoptosis pathway, thus resulting in structural and functional changes in podocytes. Our study indicated that ANLN played a vital role in maintaining the normal function of podocytes. Video Abstract.
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Affiliation(s)
- Li Lin
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Yuhong Ye
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Haidong Fu
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Weizhong Gu
- Department of Pathology, The Children's Hospital, Zhejiang University School of Medicine, 3333 Binsheng Road, Binjiang District, Hangzhou, Zhejiang, 310003, China
| | - Manli Zhao
- Department of Pathology, The Children's Hospital, Zhejiang University School of Medicine, 3333 Binsheng Road, Binjiang District, Hangzhou, Zhejiang, 310003, China
| | - Jingmiao Sun
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Zhongkai Cao
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Guoping Huang
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Yi Xie
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Fei Liu
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Lu Li
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Qiuyu Li
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China
| | - Jianhua Mao
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China.
| | - Lidan Hu
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, 3333 Binsheng Road, Binjiang District, Hangzhou, 310003, Zhejiang, China.
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Kaur A, Banday AZ, Dawman L, Rawat A, Tiewsoh K. Factors predicting the occurrence of disease-causing variants on next-generation sequencing in children with steroid-resistant nephrotic syndrome - implications for resource-constrained settings. Pediatr Nephrol 2023; 38:3663-3670. [PMID: 37335381 DOI: 10.1007/s00467-023-06042-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 04/25/2023] [Accepted: 05/15/2023] [Indexed: 06/21/2023]
Abstract
BACKGROUND Enhanced availability of high-throughput sequencing (at progressively reducing costs) has revolutionized the identification of monogenic SRNS. However, in resource-poor settings, it may not be possible to perform next-generation sequencing (NGS) in all children wherein monogenic SRNS is suspected. Besides, the optimal strategy of genetic evaluation (in patients with SRNS) in routine clinical practice in resource-limited settings is unknown. METHODS Patients with newly diagnosed SRNS were recruited from our center and followed up prospectively. We analyzed the factor(s) independently predicting the occurrence of disease-causing variants in these patients. RESULTS In our study, 36 children/adolescents with SRNS were included (initial steroid resistance in 53%). On targeted NGS, pathogenic/likely pathogenic variants were identified in 31% (n = 11). These included homozygous or compound heterozygous variants in the following genes: ALOX12B, COL4A3, CRB2, NPHS1, NPHS2, PLCE1, and heterozygous variant in WT1 gene. Overall, 14 variants were identified of which 5 (36%) were novel. Age of < 1 or < 2 years and presence of family history of nephrotic syndrome independently predicted the occurrence of monogenic SRNS on multivariate analysis. CONCLUSIONS While NGS-based genetic testing in SRNS is increasingly being incorporated in routine clinical practice the world over, the scenario is far from optimal in resource-limited settings. Our study highlights that resources for genetic testing in SRNS should be prioritized for patients with early age at disease onset and presence of family history. Larger studies composed of diverse multi-ethnic cohorts of patients with SRNS are required to further delineate the optimal strategy of genetic evaluation in resource-poor settings. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Anit Kaur
- Allergy Immunology Unit, Department of Pediatrics, Advanced Pediatrics Center, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Aaqib Zaffar Banday
- Allergy Immunology Unit, Department of Pediatrics, Advanced Pediatrics Center, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Lesa Dawman
- Nephrology Unit, Department of Pediatrics, Advanced Pediatrics Center, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, 160012, India
| | - Amit Rawat
- Allergy Immunology Unit, Department of Pediatrics, Advanced Pediatrics Center, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Karalanglin Tiewsoh
- Nephrology Unit, Department of Pediatrics, Advanced Pediatrics Center, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, 160012, India.
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Tato AM, Carrera N, García-Murias M, Shabaka A, Ávila A, Mora Mora MT, Rabasco C, Soto K, de la Prada Alvarez FJ, Fernández-Lorente L, Rodríguez-Moreno A, Huerta A, Mon C, García-Carro C, González Cabrera F, Navarro JAM, Romera A, Gutiérrez E, Villacorta J, de Lorenzo A, Avilés B, Garca-González MA, Fernández-Juárez G. Genetic testing in focal segmental glomerulosclerosis: in whom and when? Clin Kidney J 2023; 16:2011-2022. [PMID: 37915894 PMCID: PMC10616495 DOI: 10.1093/ckj/sfad193] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Indexed: 11/03/2023] Open
Abstract
Background Genetic causes are increasingly recognized in patients with focal segmental glomerulosclerosis (FSGS), but it remains unclear which patients should undergo genetic study. Our objective was to determine the frequency and distribution of genetic variants in steroid-resistant nephrotic syndrome FSGS (SRNS-FSGS) and in FSGS of undetermined cause (FSGS-UC). Methods We performed targeted exome sequencing of 84 genes associated with glomerulopathy in patients with adult-onset SRNS-FSGS or FSGS-UC after ruling out secondary causes. Results Seventy-six patients met the study criteria; 24 presented with SRNS-FSGS and 52 with FSGS-UC. We detected FSGS-related disease-causing variants in 27/76 patients (35.5%). There were no differences between genetic and non-genetic causes in age, proteinuria, glomerular filtration rate, serum albumin, body mass index, hypertension, diabetes or family history. Hematuria was more prevalent among patients with genetic causes. We found 19 pathogenic variants in COL4A3-5 genes in 16 (29.3%) patients. NPHS2 mutations were identified in 6 (16.2%) patients. The remaining cases had variants affecting INF2, OCRL, ACTN4 genes or APOL1 high-risk alleles. FSGS-related genetic variants were more common in SRNS-FSGS than in FSGS-UC (41.7% vs 32.7%). Four SRNS-FSGS patients presented with NPHS2 disease-causing variants. COL4A variants were the most prevalent finding in FSGS-UC patients, with 12 patients carrying disease-causing variants in these genes. Conclusions FSGS-related variants were detected in a substantial number of patients with SRNS-FSGS or FSGS-UC, regardless of age of onset of disease or the patient's family history. In our experience, genetic testing should be performed in routine clinical practice for the diagnosis of this group of patients.
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Affiliation(s)
- Ana María Tato
- Department of Nephrology, Hospital Universitario Fundación Alcorcón, Alcorcón, Spain
| | - Noa Carrera
- Laboratorio de Nefroloxía (No. 11), Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Instituto de investigación sanitaria de Santiago de Compostela – IDIS, Santiago de Compostela, Spain
| | - Maria García-Murias
- Laboratorio de Nefroloxía (No. 11), Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Instituto de investigación sanitaria de Santiago de Compostela – IDIS, Santiago de Compostela, Spain
| | - Amir Shabaka
- Department of Nephrology, Hospital Universitario Fundación Alcorcón, Alcorcón, Spain
| | - Ana Ávila
- Department of Nephrology, Hospital Universitario Doctor Peset, Valencia, Spain
| | | | - Cristina Rabasco
- Department of Nephrology, Hospital Universitario Reina Sofía, Córdoba, Spain
| | - Karina Soto
- Department of Nephrology, Hospital Fernando Fonseca, Lisbon, Portugal
| | | | | | | | - Ana Huerta
- Department of Nephrology, Hospital Universitario Puerta de Hierro, Majadahonda, Spain
| | - Carmen Mon
- Department of Nephrology, Hospital Universitario Severo Ochoa, Leganés, Spain
| | | | - Fayna González Cabrera
- Department of Nephrology, Hospital Universitario de Gran Canaria Doctor Negrín, Gran Canaria, Spain
| | | | - Ana Romera
- Department of Nephrology, Hospital de Ciudad Real, Ciudad Real, Spain
| | - Eduardo Gutiérrez
- Department of Nephrology, Hospital Universitario Doce de Octubre, Madrid, Spain
| | - Javier Villacorta
- Department of Nephrology, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | | | - Beatriz Avilés
- Department of Nephrology, Hospital Costa del Sol, Marbella, Spain
| | - Miguel Angel Garca-González
- Laboratorio de Nefroloxía (No. 11), Grupo de Xenética e Bioloxía do Desenvolvemento das Enfermidades Renais, Instituto de investigación sanitaria de Santiago de Compostela – IDIS, Santiago de Compostela, Spain
- Fundación Pública Galega de Medicina Xenómica-SERGAS, Complexo Hospitalario de Santiago de Compostela, Santiago de Compostela, Spain
| | - Gema Fernández-Juárez
- Department of Nephrology, Hospital Universitario La Paz, Madrid, Spain
- Instituto de Investigación de la Paz (IdIPAZ), Madrid, Spain
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Trachtman H, Diva U, Murphy E, Wang K, Inrig J, Komers R. Implications of Complete Proteinuria Remission at any Time in Focal Segmental Glomerulosclerosis: Sparsentan DUET Trial. Kidney Int Rep 2023; 8:2017-2028. [PMID: 37850006 PMCID: PMC10577371 DOI: 10.1016/j.ekir.2023.07.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 06/12/2023] [Accepted: 07/24/2023] [Indexed: 10/19/2023] Open
Abstract
Introduction Focal segmental glomerulosclerosis (FSGS) is a rare glomerular disease with high unmet clinical need. Interest in proteinuria as a surrogate end point for regulatory approval of novel treatments has increased. We assessed the relationship between achieving complete remission (CR) of proteinuria at least once during follow-up and long-term kidney outcomes. Methods This post hoc analysis included all patients enrolled in the DUET trial of sparsentan in FSGS and the open-label extension (OLE). Evaluations occurred every 12 weeks, including blood pressure (BP), edema, proteinuria, and kidney function. CR was defined as a urine protein/creatinine ratio ≤0.3g/g in a first morning urine sample. Results A total of 108 patients who received ≥1 sparsentan dose were included in this study. During a median follow-up of 47.0 months, 46 patients (43%) experienced ≥1 CR, 61% occurring within 12 months of starting sparsentan. There was an increased likelihood of CR with a higher sparsentan dose or baseline subnephrotic-range proteinuria. Achieving ≥1 CR was associated with significantly slower rate of estimated glomerular filtration rate (eGFR) decline versus non-CR patients (P < 0.05). Use of immunosuppressive agents was more frequent in patients who achieved a CR. However, the antiproteinuric effect of sparsentan was additive to that achieved with concomitant immunosuppressive treatment. No unanticipated adverse events occurred. Conclusion We conclude that sparsentan can be safely administered for extended periods and exerts a sustained antiproteinuric effect. Achievement of CR at any time during follow-up, even if it is not sustained, may be an indicator of a favorable response to treatment and a predictor of improved kidney function outcomes.
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Affiliation(s)
- Howard Trachtman
- Division of Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
| | - Ulysses Diva
- Biometrics, Travere Therapeutics, Inc., San Diego, California, USA
| | - Edward Murphy
- Biometrics, Travere Therapeutics, Inc., San Diego, California, USA
| | - Kaijun Wang
- Biometrics, Travere Therapeutics, Inc., San Diego, California, USA
| | - Jula Inrig
- Nephrology, Travere Therapeutics, Inc., San Diego, California, USA
| | - Radko Komers
- Nephrology, Travere Therapeutics, Inc., San Diego, California, USA
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Stallworth JY, Blair DR, Slavotinek A, Moore AT, Duncan JL, de Alba Campomanes AG. Retinopathy and optic atrophy in a case of COQ2-related primary coenzyme Q 10 deficiency. Ophthalmic Genet 2023; 44:486-490. [PMID: 36420660 PMCID: PMC10205914 DOI: 10.1080/13816810.2022.2141792] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 09/08/2022] [Accepted: 10/22/2022] [Indexed: 11/25/2022]
Abstract
PURPOSE To describe a case of primary coenzyme Q10 deficiency in a child manifesting as early-onset renal failure, retinal dystrophy, and optic atrophy leading to progressive vision loss. METHODS Clinical presentation and workup including visual fields, electroretinogram, and optical coherence tomography are presented. Genetic testing was performed. RESULTS An eight-year-old female with nephropathy requiring renal transplantation subsequently developed progressive cone-rod dystrophy and optic atrophy. The patient had negative results on a targeted next-generation sequencing retinal dystrophy panel but whole-exome sequencing revealed two variants in COQ2 (likely biallelic), consistent with a diagnosis of primary coenzyme Q10 deficiency. CONCLUSIONS Primary coenzyme Q10 deficiency is a rare disorder with variable systemic and ocular findings; there is also genetic heterogeneity. Genetic testing aids in the diagnosis of this condition, and variants in the COQ2 and PDSS1 genes appear to have the strongest association with ocular manifestations. Oral supplementation of coenzyme Q10 may slow progression of disease. This case highlights the utility of whole-exome sequencing in the diagnosis of a rare syndromic form of ocular disease and reports a novel phenotypic association for this condition.
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Affiliation(s)
| | - David R Blair
- Department of Pediatrics, University of California, San Francisco, CA, USA
| | - Anne Slavotinek
- Department of Pediatrics, University of California, San Francisco, CA, USA
| | - Anthony T Moore
- Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA
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Smith C, Burugula BB, Dunn I, Aradhya S, Kitzman JO, Yee JL. High-Throughput Splicing Assays Identify Known and Novel WT1 Exon 9 Variants in Nephrotic Syndrome. Kidney Int Rep 2023; 8:2117-2125. [PMID: 37850022 PMCID: PMC10577367 DOI: 10.1016/j.ekir.2023.07.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 07/31/2023] [Indexed: 10/19/2023] Open
Abstract
Introduction Frasier syndrome (FS) is a rare Mendelian form of nephrotic syndrome (NS) caused by variants which disrupt the proper splicing of WT1. This key transcription factor gene is alternatively spliced at exon 9 to produce 2 isoforms ("KTS+" and "KTS-"), which are normally expressed in the kidney at a ∼2:1 (KTS+:KTS-) ratio. FS results from variants that reduce this ratio by disrupting the splice donor of the KTS+ isoform. FS is extremely rare, and it is unclear whether any variants beyond the 8 already known could cause FS. Methods To prospectively identify other splicing-disruptive variants, we leveraged a massively parallel splicing assay. We tested every possible single nucleotide variant (n = 519) in and around WT1 exon 9 for effects upon exon inclusion and KTS+/- ratio. Results Splice disruptive variants (SDVs) made up 11% of the tested point variants overall and were tightly concentrated near the canonical acceptor and the KTS+/- alternate donors. Our map successfully identified all 8 known FS or focal segmental glomerulosclerosis (FSGS) variants and 16 additional novel variants which were comparably disruptive to these known pathogenic variants. We also identified 19 variants that, conversely, increased the KTS+/KTS- ratio, of which 2 are observed in unrelated individuals with 46,XX ovotesticular disorder of sex development (46,XX OTDSD). Conclusion This splicing effect map can serve as functional evidence to guide the clinical interpretation of newly observed variants in and around WT1 exon 9.
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Affiliation(s)
- Cathy Smith
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Bala Bharathi Burugula
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Ian Dunn
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Jacob O. Kitzman
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jennifer Lai Yee
- Department of Pediatrics, Division of Nephrology, University of Michigan, Ann Arbor, Michigan, USA
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Vivarelli M, Gibson K, Sinha A, Boyer O. Childhood nephrotic syndrome. Lancet 2023; 402:809-824. [PMID: 37659779 DOI: 10.1016/s0140-6736(23)01051-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 05/04/2023] [Accepted: 05/19/2023] [Indexed: 09/04/2023]
Abstract
Idiopathic nephrotic syndrome is the most common glomerular disease in children. Corticosteroids are the cornerstone of its treatment, and steroid response is the main prognostic factor. Most children respond to a cycle of oral steroids, and are defined as having steroid-sensitive nephrotic syndrome. Among the children who do not respond, defined as having steroid-resistant nephrotic syndrome, most respond to second-line immunosuppression, mainly with calcineurin inhibitors, and children in whom a response is not observed are described as multidrug resistant. The pathophysiology of nephrotic syndrome remains elusive. In cases of immune-mediated origin, dysregulation of immune cells and production of circulating factors that damage the glomerular filtration barrier have been described. Conversely, up to a third of cases of steroid-resistant nephrotic syndrome have a monogenic origin. Multidrug resistant nephrotic syndrome often leads to kidney failure and can cause relapse after kidney transplant. Although steroid-sensitive nephrotic syndrome does not affect renal function, most children with steroid-sensitive nephrotic syndrome have a relapsing course that requires repeated steroid cycles with significant side-effects. To minimise morbidity, some patients require steroid-sparing immunosuppressive agents, including levamisole, mycophenolate mofetil, calcineurin inhibitors, anti-CD20 monoclonal antibodies, and cyclophosphamide. Close monitoring and preventive measures are warranted at onset and during relapse to prevent acute complications (eg, hypovolaemia, acute kidney injury, infections, and thrombosis), whereas long-term management requires minimising treatment-related side-effects. A subset of patients have active disease into adulthood.
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Affiliation(s)
- Marina Vivarelli
- Division of Nephrology, Laboratory of Nephrology, Bambino Gesù Children's Hospital IRCCS, Rome, Italy.
| | - Keisha Gibson
- Division of Nephrology and Hypertension, University of North Carolina Kidney Center, University of North Carolina at Chapel Hill, NC, USA
| | - Aditi Sinha
- Division of Nephrology, Indian Council of Medical Research Center for Advanced Research in Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Olivia Boyer
- Néphrologie Pédiatrique, Centre de Référence Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Hôpital Necker - Enfants Malades, Assistance Publique Hôpitaux de Paris, Inserm U1163, Institut Imagine, Université Paris Cité, Paris, France
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Suzuki R, Sakakibara N, Ichikawa Y, Kitakado H, Ueda C, Tanaka Y, Okada E, Kondo A, Ishiko S, Ishimori S, Nagano C, Yamamura T, Horinouchi T, Okamoto T, Nozu K. Systematic Review of Clinical Characteristics and Genotype-Phenotype Correlation in LAMB2-Associated Disease. Kidney Int Rep 2023; 8:1811-1821. [PMID: 37705905 PMCID: PMC10496080 DOI: 10.1016/j.ekir.2023.06.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 05/21/2023] [Accepted: 06/21/2023] [Indexed: 09/15/2023] Open
Abstract
Introduction Laminin subunit beta-2 (LAMB2)-associated disease, termed Pierson syndrome, presents with congenital nephrotic syndrome, ocular symptoms, and neuromuscular symptoms. In recent years, however, the widespread use of next-generation sequencing (NGS) has helped to discover a variety of phenotypes associated with this disease. Therefore, we conducted this systematic review. Methods A literature search of patients with LAMB2 variants was conducted, and 110 patients were investigated, including 12 of our patients. For genotype-phenotype correlation analyses, the extracted data were investigated for pathogenic variant types, the severity of nephropathy, and extrarenal symptoms. Survival analyses were also performed for the onset age of end-stage kidney disease (ESKD). Results Among all patients, 81 (78%) presented with congenital nephrotic syndrome, and 52 (55%) developed ESKD within 12 months. The median age at ESKD onset was 6.0 months. Kidney survival analysis showed that patients with biallelic truncating variants had a significantly earlier progression to ESKD than those with other variants (median age 1.2 months vs. 60.0 months, P < 0.05). Although the laminin N-terminal domain is functionally important in laminin proteins, and variants in the laminin N-terminal domain are said to result in a severe kidney phenotype such as earlier onset age and worse prognosis, there were no significant differences in onset age of nephropathy and progression to ESKD between patients with nontruncating variants located in the laminin N-terminal domain and those with variants located outside this domain. Conclusion This study revealed a diversity of LAMB2-associated diseases, characteristics of LAMB2 nephropathy, and genotype-phenotype correlations.
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Affiliation(s)
- Ryota Suzuki
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuta Ichikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hideaki Kitakado
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Chika Ueda
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yu Tanaka
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eri Okada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Atsushi Kondo
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shingo Ishimori
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takayuki Okamoto
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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Al Riyami MS, Al Alawi I, Al Gaithi B, Al Maskari A, Al Kalbani N, Al Hashmi N, Al Balushi A, Al Shahi M, Al Saidi S, Al Bimani M, Al Hatali F, Mabillard H, Sayer JA. Genetic analysis and outcomes of Omani children with steroid-resistant nephrotic syndrome. Mol Genet Genomic Med 2023; 11:e2201. [PMID: 37204080 PMCID: PMC10496054 DOI: 10.1002/mgg3.2201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Nephrotic syndrome (NS) is one of the most common kidney disorders seen by pediatric nephrologists and is defined by the presence of heavy proteinuria (>3.5 g/24 h), hypoalbuminemia (<3.5 g/dL), edema, and hyperlipidemia. Most children with NS are steroid-responsive and have a good prognosis following treatment with prednisolone. However, 10%-20% of them have steroid-resistant nephrotic syndrome (SRNS) and fail to respond to treatment. A significant proportion of these children progress to kidney failure. METHODS This retrospective study aimed to determine the underlying genetic causes of SRNS among Omani children below 13 years old, over a 15-year period and included 77 children from 50 different families. We used targeted Sanger sequencing combined with next-generation sequencing approaches to perform molecular diagnostics. RESULTS We found a high rate of underlying genetic causes of SRNS in 61 (79.2%) children with pathogenic variants in the associated genes. Most of these genetically solved SRNS patients were born to consanguineous parents and variants were in the homozygous state. Pathogenic variants in NPHS2 were the most common cause of SRNS in our study seen in 37 (48.05%) cases. Pathogenic variants in NPHS1 were also seen in 16 cases, especially in infants with congenital nephrotic syndrome (CNS). Other genetic causes identified included pathogenic variants in LAMB2, PLCE1, MYO1E, and NUP93. CONCLUSION NPHS2 and NPHS1 genetic variants were the most common inherited causes of SRNS in Omani children. However, patients with variants in several other SRNS causative genes were also identified. We recommend screening for all genes responsible for SRNS in all children who present with this phenotype, which will assist in clinical management decisions and genetic counseling for the affected families.
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Affiliation(s)
| | - Intisar Al Alawi
- Translational and Clinical Research Institute, Faculty of Medical ScienceNewcastle UniversityNewcastle upon TyneUK
- National Genetic Center, Ministry of HealthMuscatOman
| | - Badria Al Gaithi
- Pediatric Nephrology Unit, Department of Child HealthyRoyal HospitalMuscatOman
| | - Anisa Al Maskari
- Pediatric Nephrology Unit, Department of Child HealthyRoyal HospitalMuscatOman
| | - Naifain Al Kalbani
- Pediatric Nephrology Unit, Department of Child HealthyRoyal HospitalMuscatOman
| | - Nadia Al Hashmi
- Pediatric Metabolic and Genetic Disorder UnitRoyal HospitalMuscatOman
| | - Aisha Al Balushi
- Pediatric Metabolic and Genetic Disorder UnitRoyal HospitalMuscatOman
| | - Maryam Al Shahi
- Pediatric Clinical Genetic Unit, Royal Hospital, Department of Child HealthRoyal HospitalMuscatOman
| | - Suliman Al Saidi
- Pediatric Nephrology Unit, Department of Child HealthyRoyal HospitalMuscatOman
| | | | | | - Holly Mabillard
- Translational and Clinical Research Institute, Faculty of Medical ScienceNewcastle UniversityNewcastle upon TyneUK
- Renal ServicesThe Newcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
- Newcastle Biomedical Research Center, NIHRNewcastle upon TyneUK
| | - John A. Sayer
- Translational and Clinical Research Institute, Faculty of Medical ScienceNewcastle UniversityNewcastle upon TyneUK
- Renal ServicesThe Newcastle upon Tyne Hospitals NHS Foundation TrustNewcastle upon TyneUK
- Newcastle Biomedical Research Center, NIHRNewcastle upon TyneUK
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Batool L, Hariharan K, Xu Y, Kaßmann M, Tsvetkov D, Gohlke BO, Kaden S, Gossen M, Nürnberg B, Kurtz A, Gollasch M. An inactivating human TRPC6 channel mutation without focal segmental glomerulosclerosis. Cell Mol Life Sci 2023; 80:265. [PMID: 37615749 PMCID: PMC10449997 DOI: 10.1007/s00018-023-04901-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/25/2023]
Abstract
Transient receptor potential cation channel-6 (TRPC6) gene mutations cause familial focal segmental glomerulosclerosis (FSGS), which is inherited as an autosomal dominant disease. In patients with TRPC6-related FSGS, all mutations map to the N- or C-terminal TRPC6 protein domains. Thus far, the majority of TRPC6 mutations are missense resulting in increased or decreased calcium influx; however, the fundamental molecular mechanisms causing cell injury and kidney pathology are unclear. We report a novel heterozygous TRPC6 mutation (V691Kfs*) in a large kindred with no signs of FSGS despite a largely truncated TRPC6 protein. We studied the molecular effects of V691Kfs* TRPC6 mutant using the tridimensional cryo-EM structure of the tetrameric TRPC6 protein. The results indicated that V691 is localized at the pore-forming transmembrane region affecting the ion conduction pathway, and predicted that V691Kfs* causes closure of the ion-conducting pathway leading to channel inactivation. We assessed the impact of V691Kfs* and two previously reported TRPC6 disease mutants (P112Q and G757D) on calcium influx in cells. Our data show that the V691Kfs* fully inactivated the TRCP6 channel-specific calcium influx consistent with a complete loss-of-function phenotype. Furthermore, the V691Kfs* truncation exerted a dominant negative effect on the full-length TRPC6 proteins. In conclusion, the V691Kfs* non-functional truncated TRPC6 is not sufficient to cause FSGS. Our data corroborate recently characterized TRPC6 loss-of-function and gain-of-function mutants suggesting that one defective TRPC6 gene copy is not sufficient to cause FSGS. We underscore the importance of increased rather than reduced calcium influx through TRPC6 for podocyte cell death.
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Affiliation(s)
- Lilas Batool
- BIH Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Krithika Hariharan
- BIH Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
- Fraunhofer-Institute for Biomedical Engineering (IBMT), Fraunhofer Project Center for Stem Cell Process Engineering, Würzburg, Germany
| | - Yao Xu
- Klinik und Poliklinik für Innere Medizin D-Geriatrie, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - Mario Kaßmann
- Klinik und Poliklinik für Innere Medizin D-Geriatrie, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - Dmitry Tsvetkov
- Klinik und Poliklinik für Innere Medizin D-Geriatrie, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany
| | - Björn-Oliver Gohlke
- Department of Information Technology, Science-IT, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sylvia Kaden
- Electron Microscopy Core Facility, German Cancer Research Center, Heidelberg, Germany
| | - Manfred Gossen
- BIH Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany
- Institut für Aktive Polymere, Hereon TeltowAbteilung Stammzellmodifikation und Biomaterialien, Teltow, Germany
| | - Bernd Nürnberg
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, University of Tübingen, Tübingen, Germany
| | - Andreas Kurtz
- BIH Center for Regenerative Therapies (BCRT), Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353, Berlin, Germany.
- Biomedical Data and Bioethics, Fraunhofer-Institute for Biomedical Engineering (IBMT), Berlin, Germany.
| | - Maik Gollasch
- Klinik und Poliklinik für Innere Medizin D-Geriatrie, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, Greifswald, Germany.
- Klinik für Nephrologie und Internistische Intensivmedizin, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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Saberi F, Dehghan Z, Noori E, Zali H. Identification of Renal Transplantation Rejection Biomarkers in Blood Using the Systems Biology Approach. IRANIAN BIOMEDICAL JOURNAL 2023; 27:375-87. [PMID: 38224029 PMCID: PMC10826908 DOI: 10.52547/ibj.3871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 08/19/2023] [Indexed: 01/16/2024]
Abstract
Background Renal transplantation plays an essential role in the quality of life of patients with end-stage renal disease. At least 12% of the renal patients receiving transplantations show graft rejection. One of the methods used to diagnose renal transplantation rejection is renal allograft biopsy. This procedure is associated with some risks such as bleeding and arteriovenous fistula formation. In this study, we applied a bioinformatics approach to identify serum markers for graft rejection in patients receiving a renal transplantation. Methods Transcriptomic data were first retrieved from the blood of renal transplantation rejection patients using the GEO database. The data were then used to construct the protein-protein interaction and gene regulatory networks using Cytoscape software. Next, network analysis was performed to identify hub-bottlenecks, and key blood markers involved in renal graft rejection. Lastly, the gene ontology and functional pathways related to hub-bottlenecks were detected using PANTHER and DAVID servers. Results In PPIN and GRN, SYNCRIP, SQSTM1, GRAMD1A, FAM104A, ND2, TPGS2, ZNF652, RORA, and MALAT1 were the identified critical genes. In GRN, miR-155, miR17, miR146b, miR-200 family, and GATA2 were the factors that regulated critical genes. The MAPK, neurotrophin, and TNF signaling pathways, IL-17, and human cytomegalovirus infection, human papillomavirus infection, and shigellosis were identified as significant pathways involved in graft rejection. Concusion The above-mentioned genes can be used as diagnostic and therapeutic serum markers of transplantation rejection in renal patients. The newly predicted biomarkers and pathways require further studies.
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Affiliation(s)
- Fatemeh Saberi
- Student Research Committee, Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zeinab Dehghan
- Department of Comparative Biomedical Sciences, School of Advanced Medical Sciences and Technologies, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Effat Noori
- Student Research Committee, Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Cellular and Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Hakimeh Zali
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Mantle D, Millichap L, Castro-Marrero J, Hargreaves IP. Primary Coenzyme Q10 Deficiency: An Update. Antioxidants (Basel) 2023; 12:1652. [PMID: 37627647 PMCID: PMC10451954 DOI: 10.3390/antiox12081652] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/18/2023] [Accepted: 08/19/2023] [Indexed: 08/27/2023] Open
Abstract
Coenzyme Q10 (CoQ10) has a number of vital functions in all cells, both mitochondrial and extra-mitochondrial. In addition to its key role in mitochondrial oxidative phosphorylation, CoQ10 serves as a lipid soluble antioxidant and plays an important role in fatty acid beta-oxidation and pyrimidine and lysosomal metabolism, as well as directly mediating the expression of a number of genes, including those involved in inflammation. Due to the multiplicity of roles in cell function, it is not surprising that a deficiency in CoQ10 has been implicated in the pathogenesis of a wide range of disorders. CoQ10 deficiency is broadly divided into primary and secondary types. Primary CoQ10 deficiency results from mutations in genes involved in the CoQ10 biosynthetic pathway. In man, at least 10 genes are required for the biosynthesis of functional CoQ10, a mutation in any one of which can result in a deficit in CoQ10 status. Patients may respond well to oral CoQ10 supplementation, although the condition must be recognised sufficiently early, before irreversible tissue damage has occurred. In this article, we have reviewed clinical studies (up to March 2023) relating to the identification of these deficiencies, and the therapeutic outcomes of CoQ10 supplementation; we have attempted to resolve the disparities between previous review articles regarding the usefulness or otherwise of CoQ10 supplementation in these disorders. In addition, we have highlighted several of the potential problems relating to CoQ10 supplementation in primary CoQ10 deficiency, as well as identifying unresolved issues relating to these disorders that require further research.
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Affiliation(s)
| | - Lauren Millichap
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK;
| | - Jesus Castro-Marrero
- Rheumatology Research Group, ME/CFS Research Unit, Vall d’Hebron Research Institute, Universitat Autonoma de Barcelona, 08035 Barcelona, Spain;
| | - Iain P. Hargreaves
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool L3 3AF, UK;
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46
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Ding WY, Kuzmuk V, Hunter S, Lay A, Hayes B, Beesley M, Rollason R, Hurcombe JA, Barrington F, Masson C, Cathery W, May C, Tuffin J, Roberts T, Mollet G, Chu CJ, McIntosh J, Coward RJ, Antignac C, Nathwani A, Welsh GI, Saleem MA. Adeno-associated virus gene therapy prevents progression of kidney disease in genetic models of nephrotic syndrome. Sci Transl Med 2023; 15:eabc8226. [PMID: 37556557 DOI: 10.1126/scitranslmed.abc8226] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/21/2023] [Indexed: 08/11/2023]
Abstract
Gene therapy for kidney diseases has proven challenging. Adeno-associated virus (AAV) is used as a vector for gene therapy targeting other organs, with particular success demonstrated in monogenic diseases. We aimed to establish gene therapy for the kidney by targeting a monogenic disease of the kidney podocyte. The most common cause of childhood genetic nephrotic syndrome is mutations in the podocyte gene NPHS2, encoding podocin. We used AAV-based gene therapy to rescue this genetic defect in human and mouse models of disease. In vitro transduction studies identified the AAV-LK03 serotype as a highly efficient transducer of human podocytes. AAV-LK03-mediated transduction of podocin in mutant human podocytes resulted in functional rescue in vitro, and AAV 2/9-mediated gene transfer in both the inducible podocin knockout and knock-in mouse models resulted in successful amelioration of kidney disease. A prophylactic approach of AAV 2/9 gene transfer before induction of disease in conditional knockout mice demonstrated improvements in albuminuria, plasma creatinine, plasma urea, plasma cholesterol, histological changes, and long-term survival. A therapeutic approach of AAV 2/9 gene transfer 2 weeks after disease induction in proteinuric conditional knock-in mice demonstrated improvement in urinary albuminuria at days 42 and 56 after disease induction, with corresponding improvements in plasma albumin. Therefore, we have demonstrated successful AAV-mediated gene rescue in a monogenic renal disease and established the podocyte as a tractable target for gene therapy approaches.
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Affiliation(s)
- Wen Y Ding
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Valeryia Kuzmuk
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
- Purespring Therapeutics, Rolling Stock Yard, 188 York Way, London N7 9AS, UK
| | - Sarah Hunter
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Abigail Lay
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Bryony Hayes
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Matthew Beesley
- Department of Histopathology, Cheltenham General Hospital, Cheltenham GL53 7AN, UK
| | - Ruth Rollason
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Jennifer A Hurcombe
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Fern Barrington
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Catrin Masson
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - William Cathery
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Carl May
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Jack Tuffin
- Purespring Therapeutics, Rolling Stock Yard, 188 York Way, London N7 9AS, UK
| | - Timothy Roberts
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Geraldine Mollet
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Institut Imagine, Université Paris Cité, Paris 75015, France
| | - Colin J Chu
- Academic Unit of Ophthalmology, Bristol Medical School, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Jenny McIntosh
- Research Department of Haematology, UCL Cancer Institute, Paul O'Gorman Building, University College London, London WC1E 6BT, UK
| | - Richard J Coward
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Corinne Antignac
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Institut Imagine, Université Paris Cité, Paris 75015, France
| | - Amit Nathwani
- Research Department of Haematology, UCL Cancer Institute, Paul O'Gorman Building, University College London, London WC1E 6BT, UK
| | - Gavin I Welsh
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Moin A Saleem
- Bristol Renal, Bristol Medical School, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
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Marasa M, Ahram DF, Rehman AU, Mitrotti A, Abhyankar A, Jain NG, Weng PL, Piva SE, Fernandez HE, Uy NS, Chatterjee D, Kil BH, Nestor JG, Felice V, Robinson D, Whyte D, Gharavi AG, Appel GB, Radhakrishnan J, Santoriello D, Bomback A, Lin F, D’Agati VD, Jobanputra V, Sanna-Cherchi S. Implementation and Feasibility of Clinical Genome Sequencing Embedded Into the Outpatient Nephrology Care for Patients With Proteinuric Kidney Disease. Kidney Int Rep 2023; 8:1638-1647. [PMID: 37547535 PMCID: PMC10403677 DOI: 10.1016/j.ekir.2023.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/01/2023] [Accepted: 05/22/2023] [Indexed: 08/08/2023] Open
Abstract
Introduction The diagnosis and management of proteinuric kidney diseases such as focal segmental glomerulosclerosis (FSGS) are challenging. Genetics holds the promise to improve clinical decision making for these diseases; however, it is often performed too late to enable timely clinical action and it is not implemented within routine outpatient nephrology visits. Methods We sought to test the implementation and feasibility of clinical rapid genome sequencing (GS) in guiding decision making in patients with proteinuric kidney disease in real-time and embedded in the outpatient nephrology setting. Results We enrolled 10 children or young adults with biopsy-proven FSGS (9 cases) or minimal change disease (1 case). The mean age at enrollment was 16.2 years (range 2-30). The workflow did not require referral to external genetics clinics but was conducted entirely during the nephrology standard-of-care appointments. The total turn-around-time from enrollment to return-of-results and clinical decision averaged 21.8 days (12.4 for GS), which is well within a time frame that allows clinically relevant treatment decisions. A monogenic or APOL1-related form of kidney disease was diagnosed in 5 of 10 patients. The genetic findings resulted in a rectified diagnosis in 6 patients. Both positive and negative GS findings determined a change in pharmacological treatment. In 3 patients, the results were instrumental for transplant evaluation, donor selection, and the immunosuppressive treatment. All patients and families received genetic counseling. Conclusion Clinical GS is feasible and can be implemented in real-time in the outpatient care to help guiding clinical management. Additional studies are needed to confirm the cost-effectiveness and broader utility of clinical GS across the phenotypic and demographic spectrum of kidney diseases.
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Affiliation(s)
- Maddalena Marasa
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Dina F. Ahram
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | | | - Adele Mitrotti
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | | | - Namrata G. Jain
- Division of Pediatric Nephrology, Department of Pediatrics, Columbia University, New York, USA
| | - Patricia L. Weng
- Division of Pediatric Nephrology, Department of Pediatrics, UCLA Medical Center and UCLA Medical Center-Santa Monica, Los Angeles, California, USA
| | - Stacy E. Piva
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Hilda E. Fernandez
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Natalie S. Uy
- Division of Pediatric Nephrology, Department of Pediatrics, Columbia University, New York, USA
| | - Debanjana Chatterjee
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Byum H. Kil
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Jordan G. Nestor
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | | | | | - Dilys Whyte
- Pediatric Specialty Center of Good Samaritan Hospital Medical Center, Babylon, New York, USA
| | - Ali G. Gharavi
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Gerald B. Appel
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Jai Radhakrishnan
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Dominick Santoriello
- Department of Pathology and Cell Biology, Renal Pathology Division, Columbia University Medical Center, New York, USA
| | - Andrew Bomback
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
| | - Fangming Lin
- Division of Pediatric Nephrology, Department of Pediatrics, Columbia University, New York, USA
| | - Vivette D. D’Agati
- Department of Pathology and Cell Biology, Renal Pathology Division, Columbia University Medical Center, New York, USA
| | - Vaidehi Jobanputra
- The New York Genome Center, New York, USA
- Department of Pathology and Cell Biology, Columbia University, New York, USA
| | - Simone Sanna-Cherchi
- Division of Nephrology, Department of Medicine, Columbia University, New York, USA
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Beck LH, Ayoub I, Caster D, Choi MJ, Cobb J, Geetha D, Rheault MN, Wadhwani S, Yau T, Whittier WL. KDOQI US Commentary on the 2021 KDIGO Clinical Practice Guideline for the Management of Glomerular Diseases. Am J Kidney Dis 2023; 82:121-175. [PMID: 37341661 DOI: 10.1053/j.ajkd.2023.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/20/2023] [Indexed: 06/22/2023]
Abstract
The KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases represents the first update to this set of recommendations since the initial set of KDIGO guideline recommendations was published in 2012. The pace of growth in our molecular understanding of glomerular disease has quickened and a number of newer immunosuppressive and targeted therapies have been introduced since the original set of guideline recommendations, making such an update necessary. Despite these updates, many areas of controversy remain. In addition, further updates since the publication of KDIGO 2021 have occurred which this guideline does not encompass. With this commentary, the KDOQI work group has generated a chapter-by-chapter companion opinion article that provides commentary specific to the implementation of the KDIGO 2021 guideline in the United States.
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Affiliation(s)
- Laurence H Beck
- Division of Nephrology, Department of Medicine, Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts
| | - Isabelle Ayoub
- Department of Medicine, Division of Nephrology, Wexner Medical, The Ohio State University, Columbus, Ohio
| | - Dawn Caster
- Department of Medicine, School of Medicine, University of Louisville, Louisville, Kentucky
| | | | - Jason Cobb
- Division of Renal Medicine, Department of Medicine, School of Medicine, Emory University, Atlanta, Georgia
| | - Duvuru Geetha
- Division of Nephrology, Johns Hopkins University, Baltimore, Maryland
| | - Michelle N Rheault
- Department of Pediatrics, Division of Pediatric Nephrology, Masonic Children's Hospital, University of Minnesota, Minneapolis, Minnesota
| | - Shikha Wadhwani
- Division of Nephrology and Hypertension, Northwestern University, Chicago, Illinois
| | - Timothy Yau
- Division of Nephrology, Department of Medicine, School of Medicine, Washington University, St. Louis, Missouri
| | - William L Whittier
- Division of Nephrology, Rush University Medical Center, Chicago, Illinois
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Ueda H, Tran QTH, Tran LNT, Higasa K, Ikeda Y, Kondo N, Hashiyada M, Sato C, Sato Y, Ashida A, Nishio S, Iwata Y, Iida H, Matsuoka D, Hidaka Y, Fukui K, Itami S, Kawashita N, Sugimoto K, Nozu K, Hattori M, Tsukaguchi H. Characterization of cytoskeletal and structural effects of INF2 variants causing glomerulopathy and neuropathy. Sci Rep 2023; 13:12003. [PMID: 37491439 PMCID: PMC10368640 DOI: 10.1038/s41598-023-38588-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 07/11/2023] [Indexed: 07/27/2023] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) is a common glomerular injury leading to end-stage renal disease. Monogenic FSGS is primarily ascribed to decreased podocyte integrity. Variants between residues 184 and 245 of INF2, an actin assembly factor, produce the monogenic FSGS phenotype. Meanwhile, variants between residues 57 and 184 cause a dual-faceted disease involving peripheral neurons and podocytes (Charcot-Marie-Tooth CMT/FSGS). To understand the molecular basis for INF2 disorders, we compared structural and cytoskeletal effects of INF2 variants classified into two subgroups: One (G73D, V108D) causes the CMT/FSGS phenotype, and the other (T161N, N202S) produces monogenic FSGS. Molecular dynamics analysis revealed that all INF2 variants show distinct flexibility compared to the wild-type INF2 and could affect stability of an intramolecular interaction between their N- and C-terminal segments. Immunocytochemistry of cells expressing INF2 variants showed fewer actin stress fibers, and disorganization of cytoplasmic microtubule arrays. Notably, CMT/FSGS variants caused more prominent changes in mitochondrial distribution and fragmentation than FSGS variants and these changes correlated with the severity of cytoskeletal disruption. Our results indicate that CMT/FSGS variants are associated with more severe global cellular defects caused by disrupted cytoskeleton-organelle interactions than are FSGS variants. Further study is needed to clarify tissue-specific pathways and/or cellular functions implicated in FSGS and CMT phenotypes.
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Affiliation(s)
- Hiroko Ueda
- Division of Nephrology, Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1191, Japan
| | - Quynh Thuy Huong Tran
- Division of Nephrology, Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1191, Japan
| | - Linh Nguyen Truc Tran
- Division of Nephrology, Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1191, Japan
| | - Koichiro Higasa
- Department of Genome Analysis, Institute of Biomedical Science, Kansai Medical University, Hirakata, Japan
| | - Yoshiki Ikeda
- Department of Molecular Genetics, Kansai Medical University, Hirakata, Japan
| | - Naoyuki Kondo
- Department of Molecular Genetics, Kansai Medical University, Hirakata, Japan
| | - Masaki Hashiyada
- Department of Legal Medicine, Kansai Medical University, Hirakata, Japan
| | - Chika Sato
- Department of Gynecology and Obstetrics, Kansai Medical University, Hirakata, Japan
| | - Yoshinori Sato
- Division of Nephrology, Department of Medicine, Showa University Fujigaoka Hospital, Yokohama, Kanagawa, Japan
| | - Akira Ashida
- Department of Pediatrics, Osaka Medical and Pharmaceutical University, Takatsuki, Japan
| | - Saori Nishio
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Yasunori Iwata
- Department of Nephrology and Laboratory Medicine, Kanazawa University, Kanazawa, Japan
| | - Hiroyuki Iida
- Department of Internal Medicine, Toyama Prefectural Central Hospital, Toyama, Japan
- Toyama Transplantation Promotion Foundation, Toyama, Japan
| | - Daisuke Matsuoka
- Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan
| | - Yoshihiko Hidaka
- Department of Pediatrics, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kenji Fukui
- Department of Biochemistry, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Takatsuki, Japan
| | - Suzu Itami
- Major in Science, Graduate School of Science and Engineering, Kindai University, Higashiosaka, Japan
| | - Norihito Kawashita
- Department of Energy and Materials, Faculty of Science and Engineering, Kindai University, Higashiosaka, Japan
| | - Keisuke Sugimoto
- Department of Pediatrics, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Motoshi Hattori
- Department of Pediatric Nephrology, Tokyo Women's Medical University, Tokyo, Japan
| | - Hiroyasu Tsukaguchi
- Division of Nephrology, Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi, Hirakata, Osaka, 573-1191, Japan.
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Saha A, Kapadia SF, Vala KB, Patel HV. Clinical utility of genetic testing in Indian children with kidney diseases. BMC Nephrol 2023; 24:212. [PMID: 37464296 DOI: 10.1186/s12882-023-03240-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 06/11/2023] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND Kidney diseases with genetic etiology in children present with an overlapping spectrum of manifestations. We aimed to analyze the clinical utility of genetic testing in the diagnosis and management of suspected genetic kidney diseases in children. METHODS In this retrospective study, children ≤ 18 years in whom a genetic test was ordered were included. Clinical indications for genetic testing were categorized as Glomerular diseases, nephrolithiasis and/or nephrocalcinoses, tubulopathies, cystic kidney diseases, congenital abnormality of kidney and urinary tract, chronic kidney disease of unknown aetiology and others. Clinical exome sequencing was the test of choice. Other genetic tests ordered were sanger sequencing, gene panel, multiplex ligation-dependent probe amplification and karyotyping. The pathogenicity of the genetic variant was interpreted as per the American College of Medical Genetics classification. RESULTS A total of 86 samples were sent for genetic testing from 76 index children, 8 parents and 2 fetuses. A total of 74 variants were reported in 47 genes. Out of 74 variants, 42 were missense, 9 nonsense, 12 frameshifts, 1 indel, 5 affected the splicing regions and 5 were copy number variants. Thirty-two were homozygous, 36 heterozygous and 6 were hemizygous variants. Twenty-four children (31.6%) had pathogenic and 11 (14.5%) had likely pathogenic variants. Twenty-four children (31.6%) had variants of uncertain significance. No variants were reported in 17 children (22.3%). A genetic diagnosis was made in 35 children with an overall yield of 46%. The diagnostic yield was 29.4% for glomerular diseases, 53.8% for tubular disorders, 81% for nephrolithiasis and/or nephrocalcinoses, 60% for cystic kidney diseases and 50% for chronic kidney disease of unknown etiology. Genetic testing made a new diagnosis or changed the diagnosis in 15 children (19.7%). CONCLUSION Nearly half (46%) of the children tested for a genetic disease had a genetic diagnosis. Genetic testing confirmed the clinical diagnoses, changed the clinical diagnoses or made a new diagnosis which helped in personalized management.
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Affiliation(s)
- Anshuman Saha
- Department of Pediatric Nephrology, Institute of Kidney Diseases and Research Centre, Gujarat University of Transplantation Sciences, Ahmedabad, India.
| | - Shahenaz F Kapadia
- Department of Pediatric Nephrology, Institute of Kidney Diseases and Research Centre, Gujarat University of Transplantation Sciences, Ahmedabad, India
| | - Kinnari B Vala
- Department of Pediatric Nephrology, Institute of Kidney Diseases and Research Centre, Gujarat University of Transplantation Sciences, Ahmedabad, India
| | - Himanshu V Patel
- Department of Pediatric Nephrology, Institute of Kidney Diseases and Research Centre, Gujarat University of Transplantation Sciences, Ahmedabad, India
- Department of Nephrology, Institute of Kidney Diseases and Research Centre, Gujarat University of Transplantation Sciences, Ahmedabad, India
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