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Tory K. The dominant findings of a recessive man: from Mendel's kid pea to kidney. Pediatr Nephrol 2023:10.1007/s00467-023-06238-9. [PMID: 38051388 DOI: 10.1007/s00467-023-06238-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023]
Abstract
The research of Mendel, born two centuries ago, still has many direct implications for our everyday clinical work. He introduced the terms "dominant" and "recessive" characters and determined their 3:1 ratio in the offspring of heterozygous "hybrid" plants. This distribution allowed calculation of the number of the phenotype-determining "elements," i.e., the alleles, and has been used ever since to prove the monogenic origin of a disorder. The Mendelian inheritance of monogenic kidney disorders is still of great help in distinguishing them from those with multifactorial origin in clinical practice. Inheritance of most monogenic kidney disorders fits to Mendel's observations: the equal contribution of the two parents and the complete penetrance or the direct correlation between the frequency of the recessive character and the degree of inbreeding. Nevertheless, beyond the truth of these basic concepts, several observations have expanded their genetic characteristics. The extreme genetic heterogeneity, the pleiotropy of the causal genes and the role of modifiers in ciliopathies, the digenic inheritance and parental imprinting in some tubulopathies, and the incomplete penetrance and eventual interallelic interactions in podocytopathies, reflect this expansion. For all these reasons, the transmission pattern in a natural setting may depend not only on the "character" but also on the causal gene and the variant. Mendel's passion for research combined with his modest personality and meticulous approach can still serve as an example in the work required to understand the non-Mendelian universe of genetics.
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Affiliation(s)
- Kálmán Tory
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.
- Pediatric Center, MTA Center of Excellence, Semmelweis University, Budapest, Hungary.
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Kim JH, Lim SH, Song JY, Cho MH, Hyun H, Yang EM, Lee JW, Cho MH, Park MJ, Lee JH, Jung J, Yoo KH, Jang KM, Pai KS, Suh JS, Namgoong MK, Chung WY, Kim SJ, Cho EY, Kim KM, Kim NH, Kim M, Paik JH, Kang HG, Ahn YH, Cheong HI. Genotype-phenotype correlation of X-linked Alport syndrome observed in both genders: a multicenter study in South Korea. Sci Rep 2023; 13:6827. [PMID: 37100867 PMCID: PMC10133262 DOI: 10.1038/s41598-023-34053-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/24/2023] [Indexed: 04/28/2023] Open
Abstract
The genotype-phenotype correlation of the X-linked Alport syndrome (XLAS) has been well elucidated in males, whereas it remains unclear in females. In this multicenter retrospective study, we analyzed the genotype-phenotype correlation in 216 Korean patients (male:female = 130:86) with XLAS between 2000 and 2021. The patients were divided into three groups according to their genotypes: the non-truncating group, the abnormal splicing group, and the truncating group. In male patients, approximately 60% developed kidney failure at the median age of 25.0 years, and kidney survival showed significant differences between the non-truncating and truncating groups (P < 0.001, hazard ratio (HR) 2.8) and splicing and truncating groups (P = 0.002, HR 3.1). Sensorineural hearing loss was detected in 65.1% of male patients, while hearing survival periods showed a highly significant difference between the non-truncating and truncating groups (P < 0.001, HR 5.1). In female patients, approximately 20% developed kidney failure at the median age of 50.2 years. The kidney survival was significantly different between the non-truncating and truncating groups (P = 0.006, HR 5.7). Our findings support the presence of genotype-phenotype correlation not only in male patients but also in female patients with XLAS.
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Affiliation(s)
- Ji Hyun Kim
- Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, South Korea
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, South Korea
| | - Seon Hee Lim
- Department of Pediatrics, Pusan National University Yangsan Children's Hospital and School of Medicine, Yangsan, South Korea
| | - Ji Yeon Song
- Department of Pediatrics, Pusan National University Yangsan Children's Hospital and School of Medicine, Yangsan, South Korea
| | - Myung Hyun Cho
- Department of Pediatrics, Hallym University Sacred Heart Hospital, Anyang, South Korea
| | - HyeSun Hyun
- Department of Pediatrics, College of Medicine, St. Vincent's Hospital, The Catholic University of Korea, Seoul, South Korea
| | - Eun Mi Yang
- Department of Pediatrics, Chonnam National University and School of Medicine, Gwangju, South Korea
| | - Jung Won Lee
- Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, South Korea
| | - Min Hyun Cho
- Department of Pediatrics, Kyungpook National University, School of Medicine, Daegu, South Korea
| | - Min Ji Park
- Department of Pediatrics, Kyungpook National University, School of Medicine, Daegu, South Korea
| | - Joo Hoon Lee
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, South Korea
| | - Jiwon Jung
- Department of Pediatrics, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, South Korea
| | - Kee Hwan Yoo
- Department of Nephrology, Woori Children's Hospital, Seoul, South Korea
| | - Kyung Mi Jang
- Department of Pediatrics, Yeungnam University College of Medicine, Gyeongsan, South Korea
| | - Ki Soo Pai
- Department of Pediatrics, Ajou University School of Medicine, Suwon, South Korea
| | - Jin-Soon Suh
- Department of Pediatrics, Bucheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Mee Kyung Namgoong
- Department of Pediatrics, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, South Korea
| | | | - Su Jin Kim
- Department of Pediatrics, Inha University College of Medicine, Inha University Hospital, Incheon, South Korea
| | - Eun Young Cho
- Department of Pediatrics, Chungnam National University Hospital, Daejeon, South Korea
| | - Kyung Min Kim
- Department of Pediatrics, Chungnam National University Hospital, Daejeon, South Korea
| | - Nam Hee Kim
- Department of Pediatrics, Inje University Ilsan Paik Hospital, Goyang, South Korea
| | - Minsun Kim
- Department of Pediatrics, Jeonbuk National University Medical School, Jeonju, South Korea
| | - Jin Ho Paik
- Department of Pathology, Seoul National University Bundang Hospital and Seoul National University College of Medicine, Seongnam, South Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, South Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, South Korea
- Kidney Research Institute, Medical Research Center, Seoul National University, Seoul, South Korea
| | - Yo Han Ahn
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, South Korea.
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, South Korea.
- Kidney Research Institute, Medical Research Center, Seoul National University, Seoul, South Korea.
| | - Hae Il Cheong
- Department of Pediatrics, Seoul Red Cross Hospital, Seoul, South Korea.
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Plevova P, Indrakova J, Savige J, Kuhnova P, Tvrda P, Cerna D, Hilscherova S, Kudrejova M, Polendova D, Jaklova R, Langova M, Jahnova H, Lastuvkova J, Dusek J, Gut J, Vlckova M, Solarova P, Kreckova G, Kantorova E, Soukalova J, Slavkovsky R, Zapletalova J, Tichy T, Thomasova D. A founder COL4A4 pathogenic variant resulting in autosomal recessive Alport syndrome accounts for most genetic kidney failure in Romani people. Front Med (Lausanne) 2023; 10:1096869. [PMID: 36844206 PMCID: PMC9948603 DOI: 10.3389/fmed.2023.1096869] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/11/2023] [Indexed: 02/10/2023] Open
Abstract
Introduction Romani people have a high prevalence of kidney failure. This study examined a Romani cohort for pathogenic variants in the COL4A3, COL4A4, and COL4A5 genes that are affected in Alport syndrome (AS), a common cause of genetic kidney disease, characterized by hematuria, proteinuria, end-stage kidney failure, hearing loss, and eye anomalies. Materials and methods The study included 57 Romani from different families with clinical features that suggested AS who underwent next-generation sequencing (NGS) of the COL4A3, COL4A4, and COL4A5 genes, and 83 family members. Results In total, 27 Romani (19%) had autosomal recessive AS caused by a homozygous pathogenic c.1598G>A, p.Gly533Asp variant in COL4A4 (n = 20) or a homozygous c.415G>C, p.Gly139Arg variant in COL4A3 (n = 7). For p.Gly533Asp, 12 (80%) had macroscopic hematuria, 12 (63%) developed end-stage kidney failure at a median age of 22 years, and 13 (67%) had hearing loss. For p.Gly139Arg, none had macroscopic hematuria (p = 0.023), three (50%) had end-stage kidney failure by a median age of 42 years (p = 0.653), and five (83%) had hearing loss (p = 0.367). The p.Gly533Asp variant was associated with a more severe phenotype than p.Gly139Arg, with an earlier age at end-stage kidney failure and more macroscopic hematuria. Microscopic hematuria was very common in heterozygotes with both p.Gly533Asp (91%) and p.Gly139Arg (92%). Conclusion These two founder variants contribute to the high prevalence of kidney failure in Czech Romani. The estimated population frequency of autosomal recessive AS from these variants and consanguinity by descent is at least 1:11,000 in Czech Romani. This corresponds to a population frequency of autosomal dominant AS from these two variants alone of 1%. Romani with persistent hematuria should be offered genetic testing.
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Affiliation(s)
- Pavlina Plevova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia,Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Ostrava, Czechia,*Correspondence: Pavlina Plevova,
| | - Jana Indrakova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Royal Melbourne Hospital, Melbourne, Australia
| | - Petra Kuhnova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Petra Tvrda
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Dita Cerna
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Sarka Hilscherova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Monika Kudrejova
- Department of Clinical and Molecular Pathology and Medical Genetics, University Hospital Ostrava, Ostrava, Czechia
| | - Daniela Polendova
- Department of Medical Genetics, Faculty of Medicine in Plzeň, Charles University and University Hospital Plzeň, Plzeň, Czechia
| | - Radka Jaklova
- Department of Medical Genetics, Faculty of Medicine in Plzeň, Charles University and University Hospital Plzeň, Plzeň, Czechia
| | - Martina Langova
- Department of Medical Genetics, Thomayer University Hospital, Prague, Czechia
| | - Helena Jahnova
- Department of Pediatrics, Third Faculty of Medicine, Charles University and University Hospital Královské Vinohrady, Prague, Czechia
| | - Jana Lastuvkova
- Department of Medical Genetics, Krajská zdravotní, a.s., Masaryk Hospital in Ústí nad Labem, Ústí nad Labem, Czechia
| | - Jiri Dusek
- Department of Pediatrics, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czechia
| | - Josef Gut
- Department of Pediatrics, Hospital Česká Lípa, Česká Lípa, Czechia
| | - Marketa Vlckova
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czechia
| | - Pavla Solarova
- Department of Medical Genetics, University Hospital Hradec Králové, Hradec Králové, Czechia
| | | | - Eva Kantorova
- Department of Medical Genetics, Hospital České Budějovice a.s., České Budějovice, Czechia
| | - Jana Soukalova
- Department of Medical Genetics and Genomics, University Hospital Brno, Brno, Czechia
| | - Rastislav Slavkovsky
- Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University Olomouc, Olomouc, Czechia
| | - Jana Zapletalova
- Department of Medical Biophysics, Faculty of Medicine and Dentistry, Palacký University Olomouc, Olomouc, Czechia
| | - Tomas Tichy
- Institute of Clinical and Molecular Pathology, Faculty of Medicine and Dentistry, Palacký University Olomouc, Olomouc, Czechia
| | - Dana Thomasova
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czechia
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Yuan X, Su Q, Wang H, Shi S, Liu L, Lv J, Wang S, Zhu L, Zhang H. Genetic Variants of the COL4A3 , COL4A4 , and COL4A5 Genes Contribute to Thinned Glomerular Basement Membrane Lesions in Sporadic IgA Nephropathy Patients. J Am Soc Nephrol 2023; 34:132-144. [PMID: 36130833 PMCID: PMC10101589 DOI: 10.1681/asn.2021111447] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 08/22/2022] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Thinned glomerular basement membrane (tGBM) lesions are not uncommon in IgA nephropathy (IgAN). Type IV collagen-built of α 3, α 4, and α 5 chains, encoded by COL4A3 / COL4A4 / COL4A5 genes-is the major component of glomerular basement membrane (GBM). In recent years, mutations in type IV collagen-encoding genes were also reported in patients with a histologic diagnosis of FSGS. Pathogenic COL4A3 / COL4A4 / COL4A5 variants were recently identified in familial cases of IgAN, but the contribution of these variants to sporadic IgAN is still unclear. METHODS We compared 161 patients with sporadic IgAN with tGBM lesions (IgAN-tGBM) to matched patients with IgAN without tGBM lesions and matched patients with thin basement membrane nephropathy (TBMN). Variants of COL4A3 / COL4A4 / COL4A5 genes were screened and evaluated after whole-exome sequencing. GBM thickness was measured, and levels of circulating galactose-deficient IgA1 (Gd-IgA1) were assessed by ELISA. RESULTS The patients with IgAN-tGBM manifested milder disease than did patients with IgAN without tGBM but had more severe features than the patients with TBMN. Exome sequence analysis of the 122 patients with IgAN-tGBM identified 37 diagnostic variants of the COL4A3 / COL4A4 / COL4A5 genes among 38 patients (31.1%). Furthermore, patients with IgAN-tGBM who had diagnostic variants had higher proportions of GBM thickness <250 nm and milder glomerular injury, whereas patients with IgAN-tGBM who did not have diagnostic variants showed more characteristic features of IgAN, including higher intensity of glomerular IgA deposits and elevated Gd-IgA1 levels. These findings suggest different mechanisms in patients with versus without diagnostic variants of these collagen genes. CONCLUSIONS COL4A3 / COL4A4 / COL4A5 variant detection is essential in evaluating patients with sporadic IgAN with tGBM lesions.
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Affiliation(s)
- Xiaohan Yuan
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Key Laboratory of Renal Disease (Peking University), National Health Commission, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immuno-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Qing Su
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Key Laboratory of Renal Disease (Peking University), National Health Commission, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immuno-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Hui Wang
- Laboratory of Electron Microscopy, Ultrastructural Pathology Center, Peking University First Hospital, Beijing, China
| | - Sufang Shi
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Key Laboratory of Renal Disease (Peking University), National Health Commission, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immuno-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Lijun Liu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Key Laboratory of Renal Disease (Peking University), National Health Commission, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immuno-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Jicheng Lv
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Key Laboratory of Renal Disease (Peking University), National Health Commission, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immuno-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Suxia Wang
- Laboratory of Electron Microscopy, Ultrastructural Pathology Center, Peking University First Hospital, Beijing, China
| | - Li Zhu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Key Laboratory of Renal Disease (Peking University), National Health Commission, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immuno-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
| | - Hong Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Key Laboratory of Renal Disease (Peking University), National Health Commission, Beijing, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Ministry of Education, Beijing, China
- Research Units of Diagnosis and Treatment of Immuno-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing, China
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Prevalence of hereditary tubulointerstitial kidney diseases in the German Chronic Kidney Disease study. Eur J Hum Genet 2022; 30:1413-1422. [PMID: 36100708 PMCID: PMC9712573 DOI: 10.1038/s41431-022-01177-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 07/14/2022] [Accepted: 08/15/2022] [Indexed: 11/09/2022] Open
Abstract
Hereditary chronic kidney disease (CKD) appears to be more frequent than the clinical perception. Exome sequencing (ES) studies in CKD cohorts could identify pathogenic variants in ~10% of individuals. Tubulointerstitial kidney diseases, showing no typical clinical/histologic finding but tubulointerstitial fibrosis, are particularly difficult to diagnose. We used a targeted panel (29 genes) and MUC1-SNaPshot to sequence 271 DNAs, selected in defined disease entities and age cutoffs from 5217 individuals in the German Chronic Kidney Disease cohort. We identified 33 pathogenic variants. Of these 27 (81.8%) were in COL4A3/4/5, the largest group being 15 COL4A5 variants with nine unrelated individuals carrying c.1871G>A, p.(Gly624Asp). We found three cysteine variants in UMOD, a novel missense and a novel splice variant in HNF1B and the homoplastic MTTF variant m.616T>C. Copy-number analysis identified a heterozygous COL4A5 deletion, and a HNF1B duplication/deletion, respectively. Overall, pathogenic variants were present in 12.5% (34/271) and variants of unknown significance in 9.6% (26/271) of selected individuals. Bioinformatic predictions paired with gold standard diagnostics for MUC1 (SNaPshot) could not identify the typical cytosine duplication ("c.428dupC") in any individual, implying that ADTKD-MUC1 is rare. Our study shows that >10% of selected individuals carry disease-causing variants in genes partly associated with tubulointerstitial kidney diseases. COL4A3/4/5 genes constitute the largest fraction, implying they are regularly overlooked using clinical Alport syndrome criteria and displaying the existence of phenocopies. We identified variants easily missed by some ES pipelines. The clinical filtering criteria applied enriched for an underlying genetic disorder.
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Novel and Founder Pathogenic Variants in X-Linked Alport Syndrome Families in Greece. Genes (Basel) 2022; 13:genes13122203. [PMID: 36553470 PMCID: PMC9778032 DOI: 10.3390/genes13122203] [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] [Received: 10/14/2022] [Revised: 11/08/2022] [Accepted: 11/18/2022] [Indexed: 11/27/2022] Open
Abstract
Alport syndrome (AS) is the most frequent monogenic inherited glomerulopathy and is also genetically and clinically heterogeneous. It is caused by semi-dominant pathogenic variants in the X-linked COL4A5 (NM_000495.5) gene or recessive variants in the COL4A3/COL4A4 (NM_000091.4/NM_000092.4) genes. The disease manifests in early childhood with persistent microhematuria and can progress to proteinuria and kidney failure in adolescence or early adulthood if left untreated. On biopsy, pathognomonic features include alternate thinning, thickening and lamellation of the glomerular basement membrane (GBM), in the presence of podocyte foot process effacement. Although previous studies indicate a prevalence of AS of about 1/50,000, a recent publication reported a predicted rate of pathogenic COL4A5 variants of 1/2320. We herewith present 98 patients (40 M/58 F) from 26 Greek families. We are selectively presenting the families segregating the X-linked form of AS with pathogenic variants in the COL4A5 gene. We found 21 different pathogenic variants, 12 novel: eight glycine and one proline substitutions in the collagenous domain, one cysteine substitution in the NC1 domain, two premature termination of translation codons, three splicing variants, one 5-bp insertion/frameshift variant, one indel-frameshift variant and four gross deletions. Notably, patients in six families we describe here and three families we reported previously, carried the COL4A5-p.G624D substitution, a founder defect encountered all over Europe which is hypomorphic with mostly milder symptomatology. Importantly, on several occasions, the correct genetic diagnosis reclassified patients as patients with AS, leading to termination of previous immunosuppressive/cyclosporine A therapy and a switch to angiotensin converting enzyme inhibitors (ACEi). With the understanding that all 98 patients span a wide range of ages from infancy to late adulthood, 15 patients (11 M/4 F) reached kidney failure and 11 (10 M/1 F) received a transplant. The prospects of avoiding lengthy diagnostic investigations and erroneous medications, and the advantage of delaying kidney failure with very early administration of renin-angiotensin-aldosterone system (RAAS) blockade, highlights the importance of timely documentation of AS by genetic diagnosis.
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Boeckhaus J, Hoefele J, Riedhammer KM, Nagel M, Beck BB, Choi M, Gollasch M, Bergmann C, Sonntag JE, Troesch V, Stock J, Gross O. Lifelong effect of therapy in young patients with the COL4A5 Alport missense variant p.(Gly624Asp): a prospective cohort study. Nephrol Dial Transplant 2022; 37:2496-2504. [PMID: 35022790 DOI: 10.1093/ndt/gfac006] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Angiotensin-converting enzyme inhibitors (ACEis) have evolved as a first-line therapy for delaying end-stage renal failure (ESRF) in Alport syndrome (AS). The present study tested the hypothesis of a superior nephroprotective potential of an early ACEi intervention, examining a cohort with the COL4A5 missense variant p.(Gly624Asp). METHODS In this observational cohort study (NCT02378805), 114 individuals with the identical gene variant were explored for age at ESRF and life expectancy in correlation with treatment as endpoints. RESULTS All 13 untreated hemizygous patients developed ESRF (mean age 48.9 ± 13.7 years), as did 3 very late treated hemizygotes (51.7 ± 4.2 years), with a mean life expectancy of 59.2 ± 9.6 years. All 28 earlier-treated [estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2] hemizygous patients were still alive and still had not reached ESRF. Therapy minimized the annual loss of their GFR, similar to the annual loss in healthy individuals. Of 65 heterozygotes, 4 untreated individuals developed ESRF at an age of 53.3 ± 20.7 years. None of the treated heterozygous females developed ESRF. CONCLUSIONS For the first time, this study shows that in AS, early therapy in individuals with missense variants might have the potential to delay renal failure for their lifetime and thus to improve life expectancy and quality of life without the need for renal replacement therapy. Some treated patients have reached their retirement age with still-functioning kidneys, whereas their untreated relatives have reached ESRF at the same or a younger age. Thus, in children with glomerular haematuria, early testing for Alport-related gene variants could lead to timely nephroprotective intervention.
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Affiliation(s)
- Jan Boeckhaus
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
| | - Julia Hoefele
- Institute of Human Genetics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Korbinian M Riedhammer
- Institute of Human Genetics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.,Department of Nephrology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Mato Nagel
- Center for Nephrology and Metabolic Medicine, Weisswasser, Germany
| | - Bodo B Beck
- Institute of Human Genetics, Center for Molecular Medicine Cologne, and Center for Rare and Hereditary Kidney Disease, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Mira Choi
- Department of Nephrology and Medical Intensive Care, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Maik Gollasch
- Department of Internal and Geriatric Medicine, University Medicine Greifswald, Greifswald, Germany.,Experimental and Clinical Research Center, Charité University Medicine Berlin, Berlin, Germany
| | - Carsten Bergmann
- Department of Medicine, Nephrology, University Hospital Freiburg, Germany.,Medizinische Genetik Mainz, Limbach Genetics, Mainz, Germany
| | - Joseph E Sonntag
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
| | - Victoria Troesch
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
| | - Johanna Stock
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
| | - Oliver Gross
- Clinic for Nephrology and Rheumatology, University Medical Center Göttingen, Göttingen, Germany
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8
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Savige J, Renieri A, Ars E, Daga S, Pinto AM, Rothe H, Gale DP, Aksenova M, Cerkauskaite A, Bielska O, Lipska-Zietkiewicz B, Gibson JT. Digenic Alport Syndrome. Clin J Am Soc Nephrol 2022; 17:1697-1706. [PMID: 35675912 PMCID: PMC9718039 DOI: 10.2215/cjn.03120322] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Digenic Alport syndrome refers to the inheritance of pathogenic variants in COL4A5 plus COL4A3 or COL4A4 or in COL4A3 plus COL4A4 Where digenic Alport syndrome includes a pathogenic COL4A5 variant, the consequences depend on the sex of the affected individual, COL4A5 variant "severity," and the nature of the COL4A3 or COL4A4 change. A man with a pathogenic COL4A5 variant has all his collagen IV α3α4α5-heterotrimers affected, and an additional COL4A3 or COL4A4 variant may not worsen disease. A woman with a pathogenic COL4A5 variant has on average 50% of her heterotrimers affected, which is increased to 75% with a further COL4A3 or COL4A4 variant and associated with a higher risk of proteinuria. In digenic Alport syndrome with pathogenic COL4A3 and COL4A4 variants, 75% of the heterotrimers are affected. The COL4A3 and COL4A4 genes occur head-to-head on chromosome 2, and inheritance is autosomal dominant when both variants affect the same chromosome (in cis) or recessive when they affect different chromosomes (in trans). This form of digenic disease results in increased proteinuria and a median age of kidney failure intermediate between autosomal dominant and autosomal recessive Alport syndrome. Previous guidelines have suggested that all pathogenic or likely pathogenic digenic variants should be identified and reported. Affected family members should be identified, treated, and discouraged from kidney donation. Inheritance within a family is easier to predict if the two variants are considered independently and if COL4A3 and COL4A4 variants are known to be inherited on the same or different chromosomes.
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Affiliation(s)
- Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Parkville, Victoria, Australia
| | - Alessandra Renieri
- Medical Genetics Unit, University of Siena, Siena, Italy
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
- Genetics Medica, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Elisabet Ars
- Department of Nephrology, Molecular Biology Laboratory , Fundacio Puigvert, Instituto de Investigaciones Biomédicas Sant Pau, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Sergio Daga
- Medical Genetics Unit, University of Siena, Siena, Italy
- Med Biotech Hub and Competence Center, Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Anna Maria Pinto
- Genetics Medica, Azienda Ospedaliero-Universitaria Senese, Siena, Italy
| | - Hansjorg Rothe
- Centre for Nephrology and Metabolic Disorders, Weisswasser, Germany
| | - Daniel P. Gale
- Department of Renal Medicine, University College London, London, United Kingdom
| | - Marina Aksenova
- Department of Nephrology, Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Moscow, Russia
| | - Agne Cerkauskaite
- Division of Diagnostics and Treatment of Rare Kidney and Metabolic Diseases, Institute of Biomedical Sciences, Vilnius University, Vilnius, Lithuania
| | - Olga Bielska
- Centre for Rare Diseases and Clinical Genetics Unit, Medical University of Gdansk, Gdansk, Poland
| | - Beata Lipska-Zietkiewicz
- Centre for Rare Diseases and Clinical Genetics Unit, Medical University of Gdansk, Gdansk, Poland
| | - Joel T. Gibson
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Parkville, Victoria, Australia
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Savige J. Heterozygous pathogenic COL4A3 or COL4A4 variants (AD Alport syndrome) is common, and not typically associated with end-stage kidney failure, hearing loss or ocular abnormalities. Kidney Int Rep 2022; 7:1933-1938. [PMID: 36090501 PMCID: PMC9458992 DOI: 10.1016/j.ekir.2022.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/03/2022] [Accepted: 06/01/2022] [Indexed: 12/03/2022] Open
Abstract
The term “autosomal dominant (AD) Alport syndrome” is often used to describe the condition associated with heterozygous pathogenic COL4A3 or COL4A4 variants and has largely replaced “thin basement membrane nephropathy (TBMN).” AD Alport syndrome implies that affected individuals develop end-stage kidney failure (ESKF) as well as the typical Alport hearing loss and ocular abnormalities, but these features have been considered rare with TBMN. Recent studies suggest that ESKF occurs in 14% to 30% of those with heterozygous pathogenic COL4A3 or COL4A4 variants but confirm that the hearing loss and ocular defects occur uncommonly if at all. Uncertainty over the risk of ESKF has persisted. However all the cited studies of heterozygous pathogenic COL4A3 or COL4A4 variants and kidney failure are from hospital-based patients and thus biased toward more severe disease. Multiple unselected cohorts with ESKF have found heterozygous pathogenic variants in COL4A3 and COL4A4 occur about as often as COL4A5 variants, which suggests that AD Alport syndrome causes ESKF as often as X-linked (XL) disease. In the normal population, heterozygous pathogenic COL4A3 and COL4A4 variants are present 20 times more often than COL4A5 variants. Therefore, AD Alport syndrome is complicated by ESKF 20 times less often than XL disease and occurs in fewer than 3% of those with pathogenic COL4A3 or COL4A4 variants by the age of 60. Nevertheless, individuals with heterozygous pathogenic COL4A3 or COL4A4 variants referred to a hospital are still more likely to develop impaired kidney function than those who remain at home undiagnosed.
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10
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Savige J, Huang M, Croos Dabrera MS, Shukla K, Gibson J. Genotype-Phenotype Correlations for Pathogenic COL4A3–COL4A5 Variants in X-Linked, Autosomal Recessive, and Autosomal Dominant Alport Syndrome. Front Med (Lausanne) 2022; 9:865034. [PMID: 35602506 PMCID: PMC9120524 DOI: 10.3389/fmed.2022.865034] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 03/24/2022] [Indexed: 12/28/2022] Open
Abstract
Alport syndrome is inherited as an X-linked (XL), autosomal recessive (AR), or autosomal dominant (AD) disease, where pathogenic COL4A3 – COL4A5 variants affect the basement membrane collagen IV α3α4α5 network. About 50% of pathogenic variants in each gene (major rearrangements and large deletions in 15%, truncating variants in 20%, splicing changes in 15%) are associated with “severe” disease with earlier onset kidney failure, and hearing loss and ocular abnormalities in males with XL inheritance and in males and females with AR disease. Severe variants are also associated with early proteinuria which is itself a risk factor for kidney failure. The other half of pathogenic variants are missense changes which are mainly Gly substitutions. These are generally associated with later onset kidney failure, hearing loss, and less often with major ocular abnormalities. Further determinants of severity for missense variants for XL disease in males, and in AD disease, include Gly versus non-Gly substitutions; increased distance from a non-collagenous interruption or terminus; and Gly substitutions with a more (Arg, Glu, Asp, Val, and Trp) or less disruptive (Ala, Ser, and Cys) residue. Understanding genotype-phenotype correlations in Alport syndrome is important because they help predict the likely age at kidney failure, and the need for early and aggressive management with renin-angiotensin system blockade and other therapies. Genotype-phenotype correlations also help standardize patients with Alport syndrome undergoing trials of clinical treatment. It is unclear whether severe variants predispose more often to kidney cysts or coincidental IgA glomerulonephritis which are recognized increasingly in COL4A3-, COL4A4 - and COL4A5-associated disease.
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The 2019 and 2021 International Workshops on Alport Syndrome. Eur J Hum Genet 2022; 30:507-516. [PMID: 35260866 PMCID: PMC8904161 DOI: 10.1038/s41431-022-01075-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/04/2022] [Accepted: 02/14/2022] [Indexed: 01/27/2023] Open
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12
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Kashtan CE. What the Adult Nephrologist Should Know About Alport Syndrome. Adv Chronic Kidney Dis 2022; 29:225-230. [PMID: 36084969 DOI: 10.1053/j.ackd.2021.08.003] [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: 06/25/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 11/11/2022]
Abstract
Recent trends in the diagnosis, treatment, and classification of collagen IV-associated kidney disease are likely to result in increasing numbers of people in adult nephrology practices who have a confirmed diagnosis of Alport syndrome. These trends include the increasing use of genetic testing in the diagnostic evaluation of people with hematuria, focal segmental glomerulosclerosis, and chronic kidney disease of unknown etiology; early treatment with inhibitors of the renin-angiotensin-aldosterone system to delay kidney failure; and application of an expanded definition of Alport syndrome based on genotype rather than phenotype. This commentary discusses these trends and their implications for the adult nephrologist.
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Affiliation(s)
- Clifford E Kashtan
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN.
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13
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Wopperer FJ, Knaup KX, Stanzick KJ, Schneider K, Jobst-Schwan T, Ekici AB, Uebe S, Wenzel A, Schliep S, Schürfeld C, Seitz R, Bernhardt W, Gödel M, Wiesener A, Popp B, Stark KJ, Gröne HJ, Friedrich B, Weiß M, Basic-Jukic N, Schiffer M, Schröppel B, Huettel B, Beck BB, Sayer JA, Ziegler C, Büttner-Herold M, Amann K, Heid IM, Reis A, Pasutto F, Wiesener MS. Diverse molecular causes of unsolved autosomal dominant tubulointerstitial kidney diseases. Kidney Int 2022; 102:405-420. [DOI: 10.1016/j.kint.2022.04.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 03/22/2022] [Accepted: 04/08/2022] [Indexed: 12/11/2022]
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14
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Gibson JT, Huang M, Shenelli Croos Dabrera M, Shukla K, Rothe H, Hilbert P, Deltas C, Storey H, Lipska-Ziętkiewicz BS, Chan MMY, Sadeghi-Alavijeh O, Gale DP, Cerkauskaite A, Savige J. Genotype-phenotype correlations for COL4A3-COL4A5 variants resulting in Gly substitutions in Alport syndrome. Sci Rep 2022; 12:2722. [PMID: 35177655 PMCID: PMC8854626 DOI: 10.1038/s41598-022-06525-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/24/2022] [Indexed: 12/21/2022] Open
Abstract
Alport syndrome is the commonest inherited kidney disease and nearly half the pathogenic variants in the COL4A3-COL4A5 genes that cause Alport syndrome result in Gly substitutions. This study examined the molecular characteristics of Gly substitutions that determine the severity of clinical features. Pathogenic COL4A5 variants affecting Gly in the Leiden Open Variation Database in males with X-linked Alport syndrome were correlated with age at kidney failure (n = 157) and hearing loss diagnosis (n = 80). Heterozygous pathogenic COL4A3 and COL4A4 variants affecting Gly (n = 304) in autosomal dominant Alport syndrome were correlated with the risk of haematuria in the UK 100,000 Genomes Project. Gly substitutions were stratified by exon location (1 to 20 or 21 to carboxyl terminus), being adjacent to a non-collagenous region (interruption or terminus), and the degree of instability caused by the replacement residue. Pathogenic COL4A5 variants that resulted in a Gly substitution with a highly destabilising residue reduced the median age at kidney failure by 7 years (p = 0.002), and age at hearing loss diagnosis by 21 years (p = 0.004). Substitutions adjacent to a non-collagenous region delayed kidney failure by 19 years (p = 0.014). Heterozygous pathogenic COL4A3 and COL4A4 variants that resulted in a Gly substitution with a highly destabilising residue (Arg, Val, Glu, Asp, Trp) were associated with an increased risk of haematuria (p = 0.018), and those adjacent to a non-collagenous region were associated with a reduced risk (p = 0.046). Exon location had no effect. In addition, COL4A5 variants adjacent to non-collagenous regions were over-represented in the normal population in gnomAD (p < 0.001). The nature of the substitution and of nearby residues determine the risk of haematuria, early onset kidney failure and hearing loss for Gly substitutions in X-linked and autosomal dominant Alport syndrome.
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Affiliation(s)
- Joel T Gibson
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Mary Huang
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Marina Shenelli Croos Dabrera
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Krushnam Shukla
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Hansjörg Rothe
- Centre for Nephrology and Metabolic Disorders, 02943, Weisswasser, Germany
| | - Pascale Hilbert
- Departement de Biologie Moleculaire, Institute de Pathologie et de Genetique ASBL, Gosselies, Belgium
| | - Constantinos Deltas
- Center of Excellence in Biobanking and Biomedical Research, University of Cyprus Medical School, Nicosia, Cyprus
| | - Helen Storey
- Molecular Genetics, Viapath Laboratories, 5th Floor Tower Wing, Guy's Hospital, London, SE1 9RT, UK
| | | | - Melanie M Y Chan
- Department of Renal Medicine, University College London, London, UK
| | | | - Daniel P Gale
- Department of Renal Medicine, University College London, London, UK
| | - Agne Cerkauskaite
- Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia.
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Savige J, Lipska-Zietkiewicz BS, Watson E, Hertz JM, Deltas C, Mari F, Hilbert P, Plevova P, Byers P, Cerkauskaite A, Gregory M, Cerkauskiene R, Ljubanovic DG, Becherucci F, Errichiello C, Massella L, Aiello V, Lennon R, Hopkinson L, Koziell A, Lungu A, Rothe HM, Hoefele J, Zacchia M, Martic TN, Gupta A, van Eerde A, Gear S, Landini S, Palazzo V, al-Rabadi L, Claes K, Corveleyn A, Van Hoof E, van Geel M, Williams M, Ashton E, Belge H, Ars E, Bierzynska A, Gangemi C, Renieri A, Storey H, Flinter F. Guidelines for Genetic Testing and Management of Alport Syndrome. Clin J Am Soc Nephrol 2022; 17:143-154. [PMID: 34930753 PMCID: PMC8763160 DOI: 10.2215/cjn.04230321] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Genetic testing for pathogenic COL4A3-5 variants is usually undertaken to investigate the cause of persistent hematuria, especially with a family history of hematuria or kidney function impairment. Alport syndrome experts now advocate genetic testing for persistent hematuria, even when a heterozygous pathogenic COL4A3 or COL4A4 is suspected, and cascade testing of their first-degree family members because of their risk of impaired kidney function. The experts recommend too that COL4A3 or COL4A4 heterozygotes do not act as kidney donors. Testing for variants in the COL4A3-COL4A5 genes should also be performed for persistent proteinuria and steroid-resistant nephrotic syndrome due to suspected inherited FSGS and for familial IgA glomerulonephritis and kidney failure of unknown cause.
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Affiliation(s)
- Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), The University of Melbourne, Parkville, Victoria, Australia
| | | | - Elizabeth Watson
- South West Genetic Laboratory Hub, North Bristol Trust, Bristol, United Kingdom
| | - Jens Michael Hertz
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Constantinos Deltas
- Center of Excellence in Biobanking and Biomedical Research, University of Cyprus Medical School, Nicosia, Cyprus
| | - Francesca Mari
- Department of Medical Biotechnology, Medical Genetics, University of Siena, Siena, Italy
| | - Pascale Hilbert
- Departement de Biologie Moleculaire, Institute de Pathologie et de Genetique, Gosselies, Belgium
| | - Pavlina Plevova
- Department of Medical Genetics, University Hospital of Ostrava, Ostrava, Czech Republic
- Department of Biomedical Sciences, University Hospital of Ostrava, Ostrava, Czech Republic
| | - Peter Byers
- Department of Pathology, University of Washington, Seattle, Washington
- Department of Medicine (Medical Genetics), University of Washington, Seattle, Washington
| | - Agne Cerkauskaite
- Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Martin Gregory
- Division of Nephrology, Department of Medicine, University of Utah Health, Salt Lake City, Utah
| | - Rimante Cerkauskiene
- Clinic of Pediatrics, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Danica Galesic Ljubanovic
- Department of Pathology, University of Zagreb, School of Medicine, Dubrava University Hospital, Zagreb, Croatia
| | | | | | - Laura Massella
- Division of Nephrology and Dialysis, Bambino Gesù Children's Hospital, Rome, Italy
| | - Valeria Aiello
- Department of Experimental Diagnostic and Specialty Medicine, Nephrology, Dialysis and Renal Transplant Unit, S. Orsola Hospital, University of Bologna, Bologna, Italy
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Louise Hopkinson
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Ania Koziell
- School of Immunology and Microbial Sciences, Faculty of Life Sciences, King's College London, London, United Kingdom
| | - Adrian Lungu
- Pediatric Nephrology Department, Fundeni Clinical Institute, Bucharest, Romania
| | | | - Julia Hoefele
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
| | | | | | - Asheeta Gupta
- Birmingham Children’s Hospital, Birmingham, United Kingdom
| | | | | | - Samuela Landini
- Medical Genetics Unit, Department of Clinical and Experimental Biomedical Sciences “Mario Serio,” University of Florence, Florence, Italy
| | - Viviana Palazzo
- Medical Genetics Unit, Meyer Children's University Hospital, Florence, Italy
| | - Laith al-Rabadi
- Health Sciences Centre, University of Utah, Salt Lake City, Utah
| | - Kathleen Claes
- Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Anniek Corveleyn
- Center for Human Genetics, University Hospitals and Katholieke Universiteit Leuven, Leuven, Belgium
| | - Evelien Van Hoof
- Center for Human Genetics, University Hospitals and Katholieke Universiteit Leuven, Leuven, Belgium
| | - Micheel van Geel
- Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Maggie Williams
- Bristol Genetics Laboratory Pathology Sciences, Southmead Hospital, Southmead, United Kingdom
| | - Emma Ashton
- North East Thames Regional Genetics Laboratory, Great Ormond Street Hospital, London, United Kingdom
| | - Hendica Belge
- Institut de Pathologie et de Génétique, Center for Human Genetics, Gosselies, Belgium
| | - Elisabet Ars
- Molecular Biology Laboratory, Fundacio Puigvert, Instituto de Investigaciones Biomédicas Sant Pau, Universitat Autonoma de Barcelona, Instituto de Investigación Carlos III, Barcelona, Spain
| | - Agnieszka Bierzynska
- Bristol Renal Unit, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Concetta Gangemi
- Division of Nephrology and Dialysis, University Hospital of Verona, Verona, Italy
| | - Alessandra Renieri
- Department of Medical Biotechnology, Medical Genetics, University of Siena, Siena, Italy
| | - Helen Storey
- Molecular Genetics, Viapath Laboratories, Guy’s Hospital, London, United Kingdom
| | - Frances Flinter
- Department of Clinical Genetics, Guy’s and St. Thomas’ National Health Service Foundation Trust, London, United Kingdom
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Gibson J, Fieldhouse R, Chan MM, Sadeghi-Alavijeh O, Burnett L, Izzi V, Persikov AV, Gale DP, Storey H, Savige J. Prevalence Estimates of Predicted Pathogenic COL4A3-COL4A5 Variants in a Population Sequencing Database and Their Implications for Alport Syndrome. J Am Soc Nephrol 2021; 32:2273-2290. [PMID: 34400539 PMCID: PMC8729840 DOI: 10.1681/asn.2020071065] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 05/05/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The reported prevalence of Alport syndrome varies from one in 5000 to one in 53,000 individuals. This study estimated the frequencies of predicted pathogenic COL4A3-COL4A5 variants in sequencing databases of populations without known kidney disease. METHODS Predicted pathogenic variants were identified using filtering steps based on the ACMG/AMP criteria, which considered collagen IV α3-α5 position 1 Gly to be critical domains. The population frequencies of predicted pathogenic COL4A3-COL4A5 variants were then determined per mean number of sequenced alleles. Population frequencies for compound heterozygous and digenic combinations were calculated from the results for heterozygous variants. RESULTS COL4A3-COL4A5 variants resulting in position 1 Gly substitutions were confirmed to be associated with hematuria (for each, P<0.001). Predicted pathogenic COL4A5 variants were found in at least one in 2320 individuals. p.(Gly624Asp) represented nearly half (16 of 33, 48%) of the variants in Europeans. Most COL4A5 variants (54 of 59, 92%) had a biochemical feature that potentially mitigated the clinical effect. The predicted pathogenic heterozygous COL4A3 and COL4A4 variants affected one in 106 of the population, consistent with the finding of thin basement membrane nephropathy in normal donor kidney biopsy specimens. Predicted pathogenic compound heterozygous variants occurred in one in 88,866 individuals, and digenic variants in at least one in 44,793. CONCLUSIONS The population frequencies for Alport syndrome are suggested by the frequencies of predicted pathogenic COL4A3-COL4A5 variants, but must be adjusted for the disease penetrance of individual variants and for the likelihood of already diagnosed disease and non-Gly substitutions. Disease penetrance may depend on other genetic and environmental factors.
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Affiliation(s)
- Joel Gibson
- The University of Melbourne Department of Medicine, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Rachel Fieldhouse
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Melanie M.Y. Chan
- Department of Renal Medicine, University College London, London, United Kingdom,Genomics England, Queen Mary University of London, London, United Kingdom
| | - Omid Sadeghi-Alavijeh
- Department of Renal Medicine, University College London, London, United Kingdom,Genomics England, Queen Mary University of London, London, United Kingdom
| | - Leslie Burnett
- Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Valerio Izzi
- Center for Cell-Matrix Research and Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Anton V. Persikov
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey
| | - Daniel P. Gale
- Department of Renal Medicine, University College London, London, United Kingdom,Genomics England, Queen Mary University of London, London, United Kingdom
| | - Helen Storey
- Molecular Genetics, Viapath Laboratories, Guy’s Hospital, London, United Kingdom
| | - Judy Savige
- The University of Melbourne Department of Medicine, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville, Victoria, Australia
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Savige J, Storey H, Watson E, Hertz JM, Deltas C, Renieri A, Mari F, Hilbert P, Plevova P, Byers P, Cerkauskaite A, Gregory M, Cerkauskiene R, Ljubanovic DG, Becherucci F, Errichiello C, Massella L, Aiello V, Lennon R, Hopkinson L, Koziell A, Lungu A, Rothe HM, Hoefele J, Zacchia M, Martic TN, Gupta A, van Eerde A, Gear S, Landini S, Palazzo V, al-Rabadi L, Claes K, Corveleyn A, Van Hoof E, van Geel M, Williams M, Ashton E, Belge H, Ars E, Bierzynska A, Gangemi C, Lipska-Ziętkiewicz BS. Consensus statement on standards and guidelines for the molecular diagnostics of Alport syndrome: refining the ACMG criteria. Eur J Hum Genet 2021; 29:1186-1197. [PMID: 33854215 PMCID: PMC8384871 DOI: 10.1038/s41431-021-00858-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 02/13/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023] Open
Abstract
The recent Chandos House meeting of the Alport Variant Collaborative extended the indications for screening for pathogenic variants in the COL4A5, COL4A3 and COL4A4 genes beyond the classical Alport phenotype (haematuria, renal failure; family history of haematuria or renal failure) to include persistent proteinuria, steroid-resistant nephrotic syndrome, focal and segmental glomerulosclerosis (FSGS), familial IgA glomerulonephritis and end-stage kidney failure without an obvious cause. The meeting refined the ACMG criteria for variant assessment for the Alport genes (COL4A3-5). It identified 'mutational hotspots' (PM1) in the collagen IV α5, α3 and α4 chains including position 1 Glycine residues in the Gly-X-Y repeats in the intermediate collagenous domains; and Cysteine residues in the carboxy non-collagenous domain (PP3). It considered that 'well-established' functional assays (PS3, BS3) were still mainly research tools but sequencing and minigene assays were commonly used to confirm splicing variants. It was not possible to define the Minor Allele Frequency (MAF) threshold above which variants were considered Benign (BA1, BS1), because of the different modes of inheritances of Alport syndrome, and the occurrence of hypomorphic variants (often Glycine adjacent to a non-collagenous interruption) and local founder effects. Heterozygous COL4A3 and COL4A4 variants were common 'incidental' findings also present in normal reference databases. The recognition and interpretation of hypomorphic variants in the COL4A3-COL4A5 genes remains a challenge.
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Affiliation(s)
- Judy Savige
- grid.1008.90000 0001 2179 088XDepartment of Medicine (MH and NH), The University of Melbourne, Parkville, VIC Australia
| | - Helen Storey
- grid.239826.40000 0004 0391 895XMolecular Genetics, Viapath Laboratories, Guy’s Hospital, London, UK
| | - Elizabeth Watson
- Elizabeth Watson, South West Genomic Laboratory Hub, North Bristol Trust, Bristol, UK
| | - Jens Michael Hertz
- grid.7143.10000 0004 0512 5013Jens Michael Hertz, Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Constantinos Deltas
- grid.6603.30000000121167908Center of Excellence in Biobanking and Biomedical Research and Molecule Medicine Center, University of Cyprus, Nicosia, Cyprus
| | - Alessandra Renieri
- grid.9024.f0000 0004 1757 4641Medical Genetics, University of Siena, Siena, Italy
| | - Francesca Mari
- Institute de Pathologie et de Genetique ASBL, Departement de Biologie Moleculaire, Gosselies, Belgium
| | - Pascale Hilbert
- Institute de Pathologie et de Genetique ASBL, Departement de Biologie Moleculaire, Gosselies, Belgium
| | - Pavlina Plevova
- grid.412727.50000 0004 0609 0692Department of Medical Genetics, and Department of Biomedical Sciences, University Hospital of Ostrava, Ostrava, Czech Republic
| | - Peter Byers
- grid.34477.330000000122986657Departments of Pathology and Medicine (Medical Genetics), University of Washington, Seattle, WA USA
| | - Agne Cerkauskaite
- grid.6441.70000 0001 2243 2806Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Martin Gregory
- grid.223827.e0000 0001 2193 0096Division of Nephrology, Department of Medicine, University of Utah Health, Salt Lake City, UT USA
| | - Rimante Cerkauskiene
- grid.6441.70000 0001 2243 2806Clinic of Pediatrics, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Danica Galesic Ljubanovic
- grid.412095.b0000 0004 0631 385XDepartment of Pathology, University of Zagreb, School of Medicine, Dubrava University Hospital, Zagreb, Croatia
| | - Francesca Becherucci
- grid.411477.00000 0004 1759 0844Nephrology Unit and Meyer Children’s University Hospital, Firenze, Italy
| | - Carmela Errichiello
- grid.411477.00000 0004 1759 0844Nephrology Unit and Meyer Children’s University Hospital, Firenze, Italy
| | - Laura Massella
- grid.414125.70000 0001 0727 6809Division of Nephrology and Dialysis, Bambino Gesù Children’s Hospital, IRCCS, Rome, Italy
| | - Valeria Aiello
- grid.6292.f0000 0004 1757 1758Department of Experimental Diagnostic and Specialty Medicine (DIMES), Nephrology, Dialysis and Renal Transplant Unit, S. Orsola Hospital, University of Bologna, Bologna, Italy
| | - Rachel Lennon
- grid.5379.80000000121662407Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Louise Hopkinson
- grid.5379.80000000121662407Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, Manchester, UK
| | - Ania Koziell
- grid.13097.3c0000 0001 2322 6764School of Immunology and Microbial Sciences, Faculty of Life Sciences, King’s College London, London, UK
| | - Adrian Lungu
- grid.415180.90000 0004 0540 9980Fundeni Clinical Institute, Pediatric Nephrology Department, Bucharest, Romania
| | | | - Julia Hoefele
- grid.6936.a0000000123222966Institute of Human Genetics, Technical University of Munich, München, Germany
| | | | - Tamara Nikuseva Martic
- grid.4808.40000 0001 0657 4636Department of Biology, School of Medicine University of Zagreb, Zagreb, Croatia
| | - Asheeta Gupta
- grid.415246.00000 0004 0399 7272Birmingham Children’s Hospital, Birmingham, UK
| | - Albertien van Eerde
- grid.5477.10000000120346234Departments of Genetics and Center for Molecular Medicine, University Medical Center, Utrecht University, Utrecht, The Netherlands
| | | | - Samuela Landini
- grid.8404.80000 0004 1757 2304Medical Genetics Unit, Department of Clinical and Experimental Biomedical Sciences “Mario Serio”, University of Florence, Florence, Italy
| | - Viviana Palazzo
- grid.411477.00000 0004 1759 0844Medical Genetics Unit, Meyer Children’s University Hospital, Florence, Italy
| | - Laith al-Rabadi
- grid.223827.e0000 0001 2193 0096Health Sciences Centre, University of UTAH, Salt Lake City, UT USA
| | - Kathleen Claes
- grid.410569.f0000 0004 0626 3338Department of Nephrology and Renal Transplantation, University Hospitals Leuven, Leuven, Belgium
| | - Anniek Corveleyn
- grid.410569.f0000 0004 0626 3338Center for Human Genetics, University Hospitals and KU Leuven, Leuven, Belgium
| | - Evelien Van Hoof
- grid.410569.f0000 0004 0626 3338Center for Human Genetics, University Hospitals and KU Leuven, Leuven, Belgium
| | - Micheel van Geel
- grid.412966.e0000 0004 0480 1382Department of Clinical Genetics, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Maggie Williams
- grid.416201.00000 0004 0417 1173Bristol Genetics Laboratory Pathology Sciences, Southmead Hospital, Bristol, UK
| | - Emma Ashton
- grid.420468.cNorth East Thames Regional Genetics Laboratory, Great Ormond Street Hospital, London, UK
| | - Hendica Belge
- grid.10417.330000 0004 0444 9382Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Elisabeth Ars
- grid.7080.f0000 0001 2296 0625Inherited Kidney Disorders, Fundacio Puigvert, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Agnieszka Bierzynska
- grid.5337.20000 0004 1936 7603Bristol Renal Unit, Bristol Medical School, University of Bristol, Bristol, UK
| | - Concetta Gangemi
- grid.411475.20000 0004 1756 948XDivision of Nephrology and Dialysis, University Hospital of Verona, Verona, Italy
| | - Beata S. Lipska-Ziętkiewicz
- grid.11451.300000 0001 0531 3426Centre for Rare Diseases, and Clinical Genetics Unit, Medical University of Gdansk, Gdansk, Poland
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