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Xu LL, Zhou XJ, Zhang H. An Update on the Genetics of IgA Nephropathy. J Clin Med 2023; 13:123. [PMID: 38202130 PMCID: PMC10780034 DOI: 10.3390/jcm13010123] [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: 11/09/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Immunoglobulin A (IgA) nephropathy (IgAN), the most common form of glomerulonephritis, is one of the leading causes of end-stage kidney disease (ESKD). It is widely believed that genetic factors play a significant role in the development of IgAN. Previous studies of IgAN have provided important insights to unravel the genetic architecture of IgAN and its potential pathogenic mechanisms. The genome-wide association studies (GWASs) together have identified over 30 risk loci for IgAN, which emphasizes the importance of IgA production and regulation in the pathogenesis of IgAN. Follow-up fine-mapping studies help to elucidate the candidate causal variant and the potential pathogenic molecular pathway and provide new potential therapeutic targets. With the rapid development of next-generation sequencing technologies, linkage studies based on whole-genome sequencing (WGS)/whole-exome sequencing (WES) also identify rare variants associated with IgAN, accounting for some of the missing heritability. The complexity of pathogenesis and phenotypic variability may be better understood by integrating genetics, epigenetics, and environment. We have compiled a review summarizing the latest advancements in genetic studies on IgAN. We similarly summarized relevant studies examining the involvement of epigenetics in the pathogenesis of IgAN. Future directions and challenges in this field are also proposed.
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Affiliation(s)
- Lin-Lin Xu
- Renal Division, Peking University First Hospital, Beijing 100034, China; (L.-L.X.); (H.Z.)
- Kidney Genetics Center, Peking University Institute of Nephrology, Beijing 100034, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing 100034, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing 100034, China
- State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, Beijing 100034, China
| | - Xu-Jie Zhou
- Renal Division, Peking University First Hospital, Beijing 100034, China; (L.-L.X.); (H.Z.)
- Kidney Genetics Center, Peking University Institute of Nephrology, Beijing 100034, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing 100034, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing 100034, China
- State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, Beijing 100034, China
| | - Hong Zhang
- Renal Division, Peking University First Hospital, Beijing 100034, China; (L.-L.X.); (H.Z.)
- Kidney Genetics Center, Peking University Institute of Nephrology, Beijing 100034, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing 100034, China
- Key Laboratory of Chronic Kidney Disease Prevention and Treatment, Peking University, Ministry of Education, Beijing 100034, China
- Research Units of Diagnosis and Treatment of Immune-Mediated Kidney Diseases, Chinese Academy of Medical Sciences, Beijing 100034, China
- State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, Beijing 100034, China
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Chen YT, Jiang WZ, Lu KD. Novel COL4A3 synonymous mutation causes Alport syndrome coexistent with immunoglobulin A nephropathy in a woman: A case report. World J Clin Cases 2023; 11:5947-5953. [PMID: 37727481 PMCID: PMC10506036 DOI: 10.12998/wjcc.v11.i25.5947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/31/2023] [Accepted: 08/08/2023] [Indexed: 09/01/2023] Open
Abstract
BACKGROUND Alport syndrome (AS) is an inherited disease of the glomerular basement membrane caused by mutations in genes encoding α3, α4, or α5 chains of type IV collagen. It manifests with hematuria or proteinuria, which is often accompanied by hearing impairments and ocular abnormalities. Histopathologically, AS shows mesangial proliferation and sometimes incidental immunoglobulin A (IgA) deposition. Hematuria or proteinuria is also a common presentation in patients with IgA nephropathy that makes it difficult to differentially diagnose AS and IgA nephropathy solely based on these clinical and pathological features. CASE SUMMARY Herein, we present the case of a 59-year-old female patient who was admitted to our hospital with persistent microscopic hematuria and occasional proteinuria that had lasted for > 2 years. This patient had a familial history of renal disease and was diagnosed with autosomal dominant AS (ADAS) and IgA nephropathy based on the findings of renal biopsy as well as genetic testing performed using whole-exome sequencing, which suggested that the patient carried a novel heterozygous variation (c.888G>A:p.Gln296Gln) in the COL4A3 gene that enriches the mutation spectrum of ADAS. The proband received an angiotensin receptor blocker therapy after a definitive diagnosis was established. After one year of therapy, a significant reduction in proteinuria was observed. The number of microscopic red blood cells per high-power field decreased to one-quarter of the baseline levels. Renal function also maintained well during the follow-up. CONCLUSION Our case highlights the significance of performing kidney biopsy and genetic testing in the diagnosis of AS and familial IgA nephropathy.
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Affiliation(s)
- Yu-Ting Chen
- The First Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou 310053, Zhejiang Province, China
| | - Wen-Ze Jiang
- The First Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou 310053, Zhejiang Province, China
| | - Ke-Da Lu
- Department of Nephrology, The Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310005, Zhejiang Province, China
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Zhu F, Li Y, Wang Y, Yao Y, Zeng R. The same heterozygous Col4A4 mutation triggered different renal pathological changes in Chinese family members. Front Genet 2023; 14:1180149. [PMID: 37323683 PMCID: PMC10265269 DOI: 10.3389/fgene.2023.1180149] [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: 03/07/2023] [Accepted: 05/18/2023] [Indexed: 06/17/2023] Open
Abstract
Background: Mutations in the collagen components of the glomerular basement membrane (GBM) often lead to hereditary glomerulonephritis. Previous studies have identified that autosomal dominant mutations of Col4A3, Col4A4 or Col4A5 are associated with thin basement membrane nephropathy (TBMN), Alport syndrome and other hereditary kidney diseases. However, the genetic mutations underlying other glomerulonephritis types have not been elucidated. Methods: In this study, we investigated a Chinese family with hereditary nephritis using the methods of genetic sequencing and renal biopsy. Genomic DNA was extracted from peripheral blood of the proband and her sister, and subsequently was performed genetic sequencing. They were found to have the similar mutation sites. Other family members were then validated using Sanger sequencing. The proband and her sister underwent renal puncture biopsies, and experienced pathologists performed PAS, Masson, immunofluorescence, and immunoelectron microscopic staining of the kidney tissue sections. Results: Through genetic sequencing analysis, we detected a novel heterozygous frameshift mutation c.1826delC in the COL4A4 (NM_000092.4) gene coding region, and 1 hybrid missense variation c.86G>A (p. R29Q) was also detected in the TNXB (NM_019105.6) gene coding region in several members of this Chinese family. Interestingly, we found that the same mutations caused different clinical features and distinct pathological changes in individual family members, which confirmed that pathological and genetic testing are crucial for the diagnosis and treatment of hereditary kidney diseases. Conclusion: In this study, we found a novel heterozygous mutation in Col4A4 and co-mutations of the TNXB gene in this Chinese family. Our study indicated that the same Col4A4 mutated variants produced different pathological and clinical changes in different family members. This discovery may provide novel insights into the study of hereditary kidney disease. In addition, new genetic biology techniques and renal biopsy of individual family members are essential.
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Affiliation(s)
- Fengming Zhu
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yueqiang Li
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuxi Wang
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Yao
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Nutrition, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Zeng
- Department of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Wuhan, China
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Li F, Zou H, Liu L, Xiao T, Zhang B, Zhang J. A Novel Mutation of UMOD in a Chinese Family with IgA Nephropathy: A Case Report. Case Rep Nephrol Dial 2023; 13:129-134. [PMID: 37900933 PMCID: PMC10601884 DOI: 10.1159/000531891] [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: 12/30/2022] [Accepted: 06/20/2023] [Indexed: 10/31/2023] Open
Abstract
IgA nephropathy (IgAN) is the most prevalent primary glomerulonephritis worldwide, with varying clinical presentations. The hereditary susceptibility to IgAN is rather complex. In this report, a Chinese case of IgAN was recruited. Renal biopsy showed the tubular atrophy and dilatation, but the glomerular lesions were rather weak except slight mesangial hyperplasia. Immunological staining of kidney tissue revealed the positive immunological staining of IgA and C3. By using whole-exome sequencing, a heterozygous variant in UMOD gene was found and was confirmed by Sanger sequencing. The variant in UMOD gene might contribute to the disease and this case helps understand the correlation of genotype and phenotypes of UMOD mutations.
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Affiliation(s)
- Furong Li
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology Diseases, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Huan Zou
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology Diseases, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Li Liu
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology Diseases, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Tangli Xiao
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology Diseases, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Bo Zhang
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology Diseases, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Jun Zhang
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology Diseases, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
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Xu H, Yu X, Li Y, Huang Z, Zhang L, Min Q, Bi J, Li Z, Liu L, Liang Y, Xu Z, Sun H, Yang S, Shao M. Collagen IV and Podocyte-Related Gene Variants in Patients with Concurrent IgA Nephropathy and Thin Basement Membrane Nephropathy. Nephron Clin Pract 2022; 147:301-310. [PMID: 36349777 PMCID: PMC10906470 DOI: 10.1159/000526971] [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: 01/14/2022] [Accepted: 08/30/2022] [Indexed: 03/03/2024] Open
Abstract
INTRODUCTION IgA nephropathy is the most common primary glomerulonephritis among adults in clinic. Thin basement membrane nephropathy is often underestimated or even omitted if it coincides with IgA nephropathy. Therefore, it is necessary to study the epidemiological, clinical, and molecular characteristics of the concurrence of this entity. METHODS Eight patients with concurrent IgA nephropathy and thin basement membrane nephropathy (IgA-T) were retrospectively analyzed based on their clinicopathological characteristics. Genetic analysis was performed using whole-exome sequencing and Sanger's sequencing. Data of the patients with IgA nephropathy and normal basement membrane (IgA-N) and variants in the local in-house database were used as controls. All candidate variants were assessed in silico. RESULTS The clinical manifestations of patients with IgA-T were hematuria, proteinuria, and renal insufficiency. Histopathological analysis showed mild mesangial hyperplasia, focal segmental glomerulosclerosis, podocyte activation, and foot process fusion. Crescent was rarely seen. COL4A and/or podocyte cytoskeleton and mitochondria-related gene variants were detected in seven IgA-T patients. Three patients exhibited pathogenic variants of COL4A, including a new variant. All IgA-T and one IgA-N patient possessed ITGB4 and/or PLEC variants, but there was no corresponding genotype-phenotype relationship. Six patients possessed other podocyte cytoskeleton and mitochondria-related gene variants such as NPHS2, SRGAP1, MYO1E, MYO1C, WT1, and COQ9, which were first reported in patients with IgA-T and were not in controls. Altogether, there were no significant differences in the degrees of proteinuria, serum creatinine, and eGFR during the follow-up period of 5-10 years, but there was a significant difference in the degree of proteinuria between IgA-T patients with podocyte-related gene variants and IgA-N patients. In the IgA-T group, patients with podocyte-related gene variants seemed predisposed to progress than patients without those variants, with higher proteinuria and serum creatinine and reduced eGFR. CONCLUSION Concurrent thin basement membrane nephropathy and/or heterozygous COL4A gene pathogenic variants do not necessarily predict the short-term progress of sporadic IgA nephropathy in adults. Predisposition factors for this disease progression should be considered for detecting the variants of COL4A and podocyte cytoskeleton and mitochondria-related genes simultaneously, which also manifests the complexity and heterogeneity of IgA nephropathy with concurrent thin basement membrane nephropathy.
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Affiliation(s)
- Hua Xu
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - XueWen Yu
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Yun Li
- Department of Nephrology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - ZhongHua Huang
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - Lu Zhang
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - QinQin Min
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - JiaXin Bi
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - ZhenGuo Li
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - LingYun Liu
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - YingYing Liang
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - ZhouWen Xu
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - HuiLi Sun
- Department of Nephrology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - ShuDong Yang
- Department of Nephrology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
| | - MuMin Shao
- Department of Pathology, The Fourth Clinical Medical College of Guangzhou University of Chinese Medicine, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen, China
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García-Aznar JM, De la Higuera L, Besada Cerecedo L, Gandiaga NP, Vega AI, Fernández-Fresnedo G, González-Lamuño D. New Insights into Renal Failure in a Cohort of 317 Patients with Autosomal Dominant Forms of Alport Syndrome: Report of Two Novel Heterozygous Mutations in COL4A3. J Clin Med 2022; 11:jcm11164883. [PMID: 36013122 PMCID: PMC9409901 DOI: 10.3390/jcm11164883] [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: 05/19/2022] [Revised: 07/27/2022] [Accepted: 08/12/2022] [Indexed: 11/24/2022] Open
Abstract
Alport syndrome (AS) is a clinically and genetically heterogeneous disorder with a wide phenotypic spectrum, onset, and progression. X-linked AS (XLAS) and autosomal recessive AS (ARAS) are severe conditions, whereas the severity of autosomal dominant AS (ADAS) may vary from benign familial hematuria to progressive renal disease with extra-renal manifestations. In this study, we collated information from the literature and analyzed a cohort of 317 patients with ADAS carrying heterozygous disease-causing mutations in COL4A3/4 including four patients from two unrelated families who carried two novel variants in COL4A3. Regarding the age of onset of the disease, 80% of patients presented urinalysis alterations (microhematuria, hematuria, and/or proteinuria) before the age of 40 years. The cumulative probability of suffering adverse renal events was mainly observed between 30 and 70 years, without statistical differences between COL4A3 and COL4A4. We observed statistically significant differences between the sexes in the age of developing ESKD in cases affected by mutations in COL4A3/4 (p value = 0.0097), suggesting that males begin experiencing earlier deterioration of renal function than women. This study supports the importance of follow-up in young patients who harbor pathogenic mutations in COL4A3/4. We update the knowledge of ADAS, highlighting differences in the progression of the disease between males and females.
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Affiliation(s)
| | | | | | - Nerea Paz Gandiaga
- Servicio de Genética, Hospital Universitario Marqués de Valdecilla, 39008 Santander, Spain
| | - Ana Isabel Vega
- Servicio de Genética, Hospital Universitario Marqués de Valdecilla, 39008 Santander, Spain
| | - Gema Fernández-Fresnedo
- Servicio de Nefrología, Hospital Universitario Marqués de Valdecilla, 39008 Santander, Spain
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Li Q, Zhu L, Shi S, Xu D, Lv J, Zhang H. Case Report: A Pathogenic Missense Variant of WT1 Cosegregates With Proteinuria in a Six-Generation Chinese Family With IgA Nephropathy. Front Med (Lausanne) 2022; 8:810940. [PMID: 35174184 PMCID: PMC8841721 DOI: 10.3389/fmed.2021.810940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 12/30/2021] [Indexed: 11/13/2022] Open
Abstract
Immunoglobulin A (IgA) nephropathy (IgAN) is the most common type of primary glomerulonephritis worldwide. In addition to hematuria, proteinuria is observed in a considerable proportion of patients with IgAN and has proven to be a strong risk factor for disease progression. Although the exact pathogenesis of IgAN is still unclear, genetic factors are widely considered to play a role in its occurrence and development. Here, we investigated a large IgAN-associated pedigree of 47 members belonging to six generations. Two members of the family who presented with proteinuria and hematuria were diagnosed with IgAN through renal biopsy. Four other members also exhibited proteinuria or hematuria but without renal biopsy. Using whole-exome sequencing, we identified a likely pathogenic variant in WT1 (c.1397C>T; p.Ser466Phe) that cosegregated with proteinuria in the affected family members. In addition, another pathogenic variant in NPHS1 (c.3478C>T; p.Arg1160Ter) was identified; however, it did not cosegregate with abnormal proteinuria. Compared to individuals in the pedigree with only one heterozygous WT1 variant (c.1397C>T; p.Ser466Phe), the proband and her younger brother carried an additional WT1 variant (c.1433-10G>A) and presented with a more severe phenotype and rapid progression to end-stage kidney disease. Our findings suggest the WT1 missense variant (c.1397C>T; p.Ser466Phe)-induced primary podocyte injury might contribute to the proteinuria phenotype and IgAN progression in this pedigree.
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Elhassan EAE, Murray SL, Connaughton DM, Kennedy C, Cormican S, Cowhig C, Stapleton C, Little MA, Kidd K, Bleyer AJ, Živná M, Kmoch S, Fennelly NK, Doyle B, Dorman A, Griffin MD, Casserly L, Harris PC, Hildebrandt F, Cavalleri GL, Benson KA, Conlon PJ. The utility of a genetic kidney disease clinic employing a broad range of genomic testing platforms: experience of the Irish Kidney Gene Project. J Nephrol 2022; 35:1655-1665. [PMID: 35099770 PMCID: PMC9300532 DOI: 10.1007/s40620-021-01236-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/16/2021] [Indexed: 10/24/2022]
Abstract
BACKGROUND AND AIMS Genetic testing presents a unique opportunity for diagnosis and management of genetic kidney diseases (GKD). Here, we describe the clinical utility and valuable impact of a specialized GKD clinic, which uses a variety of genomic sequencing strategies. METHODS In this prospective cohort study, we undertook genetic testing in adults with suspected GKD according to prespecified criteria. Over 7 years, patients were referred from tertiary centres across Ireland to an academic medical centre as part of the Irish Kidney Gene Project. RESULTS Among 677 patients, the mean age was of 37.2 ± 13 years, and 73.9% of the patients had family history of chronic kidney disease (CKD). We achieved a molecular diagnostic rate of 50.9%. Four genes accounted for more than 70% of identified pathogenic variants: PKD1 and PKD2 (n = 186, 53.4%), MUC1 (8.9%), and COL4A5 (8.3%). In 162 patients with a genetic diagnosis, excluding PKD1/PKD2, the a priori diagnosis was confirmed in 58% and in 13% the diagnosis was reclassified. A genetic diagnosis was established in 22 (29.7%) patients with CKD of uncertain aetiology. Based on genetic testing, a diagnostic kidney biopsy was unnecessary in 13 (8%) patients. Presence of family history of CKD and the underlying a priori diagnosis were independent predictors (P < 0.001) of a positive genetic diagnosis. CONCLUSIONS A dedicated GKD clinic is a valuable resource, and its implementation of various genomic strategies has resulted in a direct, demonstrable clinical and therapeutic benefits to affected patients.
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Affiliation(s)
- Elhussein A E Elhassan
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland. .,Department of Medicine, Dublin, Royal College of Surgeons in Ireland, Dublin, Ireland.
| | - Susan L Murray
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland.,Department of Medicine, Dublin, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Dervla M Connaughton
- Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.,Division of Nephrology, Department of Medicine, London Health Sciences Centre, London, ON, Canada
| | - Claire Kennedy
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Sarah Cormican
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Cliona Cowhig
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland
| | - Caragh Stapleton
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons, Dublin, Ireland
| | - Mark A Little
- Trinity Health Kidney Centre, Trinity Translational Medicine Institute, Trinity College Dublin, St James' Street, Dublin 8, Ireland
| | - Kendrah Kidd
- Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Anthony J Bleyer
- Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Martina Živná
- Research Unit for Rare Diseases, Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
| | - Stanislav Kmoch
- Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Research Unit for Rare Diseases, Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
| | | | - Brendan Doyle
- Department of Pathology, Beaumont Hospital, Dublin, Ireland
| | - Anthony Dorman
- Department of Pathology, Beaumont Hospital, Dublin, Ireland.,Department of Pathology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Matthew D Griffin
- Nephrology Department, Galway University Hospitals, Saolta University Healthcare Group, Galway, Ireland.,Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, School of Medicine, National University of Ireland, Galway, Ireland
| | - Liam Casserly
- Department of Nephrology and Internal Medicine, University Hospital Limerick, Limerick, Ireland
| | - Peter C Harris
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Friedhelm Hildebrandt
- Department of Paediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Gianpiero L Cavalleri
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons, Dublin, Ireland
| | - Katherine A Benson
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons, Dublin, Ireland
| | - Peter J Conlon
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland.,Department of Medicine, Dublin, Royal College of Surgeons in Ireland, Dublin, Ireland
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Bhattacharyya A, Huang Y, Khan SH, Drachenberg CB, Malone LC. Tale of two nephropathies; co-occurring Alport syndrome and IgA nephropathy, a case report. BMC Nephrol 2021; 22:358. [PMID: 34717572 PMCID: PMC8557485 DOI: 10.1186/s12882-021-02567-9] [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: 05/25/2021] [Accepted: 10/13/2021] [Indexed: 11/20/2022] Open
Abstract
Background Alport Syndrome and IgA Nephropathy (IgAN) are both disorders that can cause hematuria. Alport syndrome is most commonly an X-linked disease, caused by COL4A5 mutation. Mutations of COL4A3 and COL4A4 on chromosome two are also common causes of Alport syndrome. IgAN is the most common glomerulonephritis worldwide. Though IgAN is usually sporadic, an estimated 15% of cases have an inheritable component. These cases of Familal IgA Nephropathy (FIgAN) can have mutations on genes which are known to cause Alport Syndrome. Case presentation We report a case of a 27-year-old man with strong family history of renal disease, who presented with hematuria and new non-nephrotic range proteinuria. Physical exam showed no abnormalities. His creatinine remained persistently elevated, and renal ultrasound exhibited bilaterally increased echogenicity consistent with Chronic Kidney Disease. Twenty-four-hour urinary collection revealed non-nephrotic range proteinuria of 1.4 g, with otherwise negative workup. On biopsy, he had IgA positive immunofluorescent staining as well as moderate interstitial fibrosis and tubular atrophy. Electron microscopy showed a basket-weave pattern of thickening and splitting of the lamina densa-consistent with Alport Syndrome, as well as mesangial expansion with electron-dense deposits -consistent with IgAN. Conclusions Mutations of COL4A5 on the X chromosome, as well as mutations of COL4A3 and COL4A4 on chromosome 2, can cause both Alport Syndrome and FIgAN. Genome wide association studies identified certain Angiotensin Converting Enzyme gene polymorphisms as independent risk factors for progression of IgAN. Our Presentation with this co-occurring pathology suggests a new paradigm where Alport Syndrome and FIgAN may represent manifestations of a single disease spectrum rather than two disparate pathologies. Appreciating hematuria through this framework has implications for treatments and genetic counseling. Further genome wide association studies will likely increase our understanding of Alport Syndrome, FIgAN, and other causes of hematuria.
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Affiliation(s)
- Aniruddha Bhattacharyya
- Department of Medicine, University of Maryland Medical Center Midtown Campus, Baltimore, MD, 21201, USA
| | - Yuting Huang
- Department of Medicine, University of Maryland Medical Center Midtown Campus, Baltimore, MD, 21201, USA
| | - Sarah Hussain Khan
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Cinthia Beskow Drachenberg
- Department of Pathology, University of Maryland School of Medicine, 22 South Greene St., Baltimore, MD, 21201, USA
| | - Laura C Malone
- Department of Pathology, University of Maryland School of Medicine, 22 South Greene St., Baltimore, MD, 21201, USA.
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10
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Savige J, Harraka P. Pathogenic Variants in the Genes Affected in Alport Syndrome (COL4A3-COL4A5) and Their Association With Other Kidney Conditions: A Review. Am J Kidney Dis 2021; 78:857-864. [PMID: 34245817 DOI: 10.1053/j.ajkd.2021.04.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 04/23/2021] [Indexed: 01/15/2023]
Abstract
Massively Parallel Sequencing identifies pathogenic variants in the genes affected in Alport syndrome (COL4A3 - COL4A5) in up to 30 % of individuals with focal and segmental glomerulosclerosis (FSGS), 10 % of those with kidney failure of unknown cause and 20 % with familial IgA glomerulonephritis. FSGS associated with COL4A3 - COL4A5 variants is usually present by kidney failure onset and may develop because the abnormal glomerular membranes result in podocyte loss and secondary hyperfiltration. The association of COL4A3 - COL4A5 variants with kidney failure or IgA glomerulonephritis may be coincidental and not pathogenic. However, since some of these variants occur more often than they should by chance, some may be pathogenic. COL4A3 - COL4A5 variants are sometimes also found in cystic kidney diseases after autosomal dominant polycystic kidney disease (ADPKD) has been excluded. COL4A3 - COL4A5 variants should be suspected in individuals with FSGS, kidney failure of unknown cause, or familial IgA glomerulonephritis, especially where there is persistent haematuria, and a family history of haematuria or kidney failure.
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Affiliation(s)
- Judy Savige
- The University of Melbourne Department of Medicine, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville VIC 3050 AUSTRALIA.
| | - Philip Harraka
- The University of Melbourne Department of Medicine, Melbourne Health and Northern Health, Royal Melbourne Hospital, Parkville VIC 3050 AUSTRALIA
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11
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Altun I, Saygılı S, Canpolat N, Özlük Y, Hürdoğan Ö, Yeşil G, Çalışkan S, Sever L. Strong mesangial IgA staining-does it always refer to IgA nephropathy in a patient with proteinuria and hematuria? Answers. Pediatr Nephrol 2021; 36:2043-2045. [PMID: 33459929 DOI: 10.1007/s00467-020-04899-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 12/01/2020] [Indexed: 01/28/2023]
Affiliation(s)
- Ilayda Altun
- Department of Pediatrics, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Seha Saygılı
- Department of Pediatric Nephrology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey.
| | - Nur Canpolat
- Department of Pediatric Nephrology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Yasemin Özlük
- Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Özge Hürdoğan
- Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Gözde Yeşil
- Department of Medical Genetics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Salim Çalışkan
- Department of Pediatric Nephrology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Lale Sever
- Department of Pediatric Nephrology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
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12
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Sato Y, Tsukaguchi H, Higasa K, Kawata N, Inui K, Linh TNT, Quynh TTH, Yoshihiko I, Koiwa F, Yoshimura A. Positive renal familial history in IgA nephropathy is associated with worse renal outcomes: a single-center longitudinal study. BMC Nephrol 2021; 22:230. [PMID: 34147067 PMCID: PMC8214250 DOI: 10.1186/s12882-021-02425-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 05/31/2021] [Indexed: 12/01/2022] Open
Abstract
Background IgA nephropathy (IgAN) is the most common primary glomerulonephritis worldwide. Although most IgAN cases are sporadic, few show a familial aggregation. However, the prevalence and prognosis of IgAN individuals with positive familial history (FH) of renal disorders remains uncertain. To address these issues, we conducted a longitudinal observational study on a single-institution cohort of patients with biopsy-proven IgAN. Methods A total of 467 IgAN patients who underwent renal biopsy during 1994 to 2019 were ascertained to have positive- or negative-FH by history taking and were followed for an average of 8.9 years. We compared the clinical and pathological features of the two subgroups. The primary outcome, a composite of a hard endpoint (end-stage renal disease [ESRD]) and surrogate endpoint (a 50% or more reduction in the estimated glomerular filtration rate [eGFR] from baseline), was evaluated. To estimate the risk for progression to ESRD, a Cox proportional hazards analysis was performed for a subset of patients who underwent follow-up for > 2 years and had an eGFR > 30 mL/min/1.73 m2 at baseline (n = 389; observation, 8.7 years). Results Positive-FH subtype accounted for 11.6% (n = 54) of all IgAN patients. At baseline, there were no significant differences between the positive- and negative-FH subgroups regarding age, sex, comorbid disease, MEST-C score, observation period, and therapeutic interventions. However, the eGFR value at baselines was significantly lower in the positive-FH subgroup than in the negative-FH subgroup (P < 0.01). On multivariate analysis, positive-FH emerged an independent determinant of poorer renal outcomes (odds ratio, 2.31; 95% confidence interval, 1.10–4.85; P = 0.03), after adjusting for confounding factors. eGFR at follow-up was significantly lower in the positive-FH subgroup than in the negative-FH subgroup after adjustment for age and observation period. Conclusions Positive-FH was found in 11.6% of all IgAN patients, consistent with the incidence seen in previous literature. A significantly lower eGFR at baseline and last follow-up and unfavorable renal outcomes in the positive-FH subgroup suggest that certain genetic risk factors predisposing to renal failure may exist in a fraction of our IgAN cohort. (331 words). Supplementary Information The online version contains supplementary material available at 10.1186/s12882-021-02425-8.
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Affiliation(s)
- Yoshinori Sato
- Department of Internal Medicine, Division of Nephrology, Showa University School of Medicine, Fujigaoka Hospital, 1-30 Fujigaoka, Aobaku, Yokohama, Kanagawa, 227-8501, Japan.
| | - Hiroyasu Tsukaguchi
- 2nd Department of Internal Medicine, Kansai Medical University, Hirakata, Osaka 573-1010, Japan
| | - Koichiro Higasa
- Department of Genome Analysis, Institute of Biomedical Science, Kansai Medical University, Hirakata, Osaka 573-1010, Japan
| | - Naoto Kawata
- Department of Internal Medicine, Division of Nephrology, Showa University School of Medicine, Fujigaoka Hospital, 1-30 Fujigaoka, Aobaku, Yokohama, Kanagawa, 227-8501, Japan
| | - Kiyoko Inui
- Department of Internal Medicine, Division of Nephrology, Showa University School of Medicine, Fujigaoka Hospital, 1-30 Fujigaoka, Aobaku, Yokohama, Kanagawa, 227-8501, Japan
| | - Tran Nguyen Truc Linh
- 2nd Department of Internal Medicine, Kansai Medical University, Hirakata, Osaka 573-1010, Japan
| | - Tran Thuy Huong Quynh
- 2nd Department of Internal Medicine, Kansai Medical University, Hirakata, Osaka 573-1010, Japan
| | - Inoue Yoshihiko
- Department of Internal Medicine, Division of Nephrology, Showa University School of Medicine, Fujigaoka Hospital, 1-30 Fujigaoka, Aobaku, Yokohama, Kanagawa, 227-8501, Japan
| | - Fumihiko Koiwa
- Department of Internal Medicine, Division of Nephrology, Showa University School of Medicine, Fujigaoka Hospital, 1-30 Fujigaoka, Aobaku, Yokohama, Kanagawa, 227-8501, Japan
| | - Ashio Yoshimura
- Department of Internal Medicine, Division of Nephrology, Showa University School of Medicine, Fujigaoka Hospital, 1-30 Fujigaoka, Aobaku, Yokohama, Kanagawa, 227-8501, Japan.,Shinyokohama-Daiichi Clinic, Yokohama, Kanagawa, Japan
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13
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Utility of glomerular Gd-IgA1 staining for indistinguishable cases of IgA nephropathy or Alport syndrome. Clin Exp Nephrol 2021; 25:779-787. [PMID: 33743099 DOI: 10.1007/s10157-021-02054-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/11/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Pathological findings in Alport syndrome frequently show mesangial proliferation and sometimes incidental IgA deposition, in addition to unique glomerular basement membrane (GBM) changes including thin basement membrane and/or lamellation. However, similar GBM abnormalities are also often observed in IgA nephropathy. Both diseases are also known to show hematuria, proteinuria, and sometimes macrohematuria when associated with viral infection. Therefore, it can be difficult to make a differential diagnosis, even based on clinical and pathological findings. Some recent articles demonstrated that galactose-deficient IgA1 (Gd-IgA1)-specific monoclonal antibody (KM55) could potentially enable incidental IgA deposition to be distinguished from IgA nephropathy. METHODS We performed comprehensive gene screening and glomerular Gd-IgA1 and type IV collagen α5 chain immunostaining for five cases with both IgA deposition and GBM changes to confirm that Gd-IgA1 can help to distinguish these two diseases. RESULTS Four of the cases were genetically diagnosed with Alport syndrome (Cases 1-4) and one was IgA nephropathy with massive GBM changes, which had a negative gene test result (Case 5). In Cases 1-4, glomerular Gd-IgA1 deposition was not detected, although there was positivity for IgA in the mesangial area. In Case 5, glomerular Gd-IgA1 deposition was observed. CONCLUSION Gd-IgA1 expression analysis could clearly differentiate these two disorders. This approach can be applied to identify these two diseases showing identical clinical and pathological findings.
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14
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Murray SL, Fennelly NK, Doyle B, Lynch SA, Conlon PJ. Integration of genetic and histopathology data in interpretation of kidney disease. Nephrol Dial Transplant 2020; 35:1113-1132. [PMID: 32777081 DOI: 10.1093/ndt/gfaa176] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Indexed: 12/22/2022] Open
Abstract
For many years renal biopsy has been the gold standard for diagnosis in many forms of kidney disease. It provides rapid, accurate and clinically useful information in most individuals with kidney disease. However, in recent years, other diagnostic modalities have become available that may provide more detailed and specific diagnostic information in addition to, or instead of, renal biopsy. Genomics is one of these modalities. Previously prohibitively expensive and time consuming, it is now increasingly available and practical in a clinical setting for the diagnosis of inherited kidney disease. Inherited kidney disease is a significant cause of kidney disease, in both the adult and paediatric populations. While individual inherited kidney diseases are rare, together they represent a significant burden of disease. Because of the heterogenicity of inherited kidney disease, diagnosis and management can be a challenge and often multiple diagnostic modalities are needed to arrive at a diagnosis. We present updates in genomic medicine for renal disease, how genetic testing integrates with our knowledge of renal histopathology and how the two modalities may interact to enhance patient care.
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Affiliation(s)
- Susan L Murray
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland.,Department of Medicine, Royal College of Surgeons, Dublin, Ireland
| | | | - Brendan Doyle
- Department of Pathology, Beaumont Hospital, Dublin, Ireland
| | - Sally Ann Lynch
- National Rare Disease Office Mater Hospital Dublin, Dublin, Ireland
| | - Peter J Conlon
- Department of Nephrology and Transplantation, Beaumont Hospital, Dublin, Ireland.,Department of Medicine, Royal College of Surgeons, Dublin, Ireland
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15
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IgA nephropathy in children and in adults: two separate entities or the same disease? J Nephrol 2020; 33:1219-1229. [PMID: 32314305 DOI: 10.1007/s40620-020-00725-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 03/12/2020] [Indexed: 12/17/2022]
Abstract
IgA nephropathy (IgAN) is observed in subjects of any age, however perspective and management of this disease are different between adult and pediatrician Nephrologists. Most children with IgAN present with gross hematuria rapidly vanishing or persistent mild microscopic hematuria, which rarely progresses to end stage renal disease (ESRD) over the pediatric observation. The perspective of IgAN in adults is of a slowly progressive glomerular disease with 30-40% probabilities to reach ESRD. However, mild cases of IgAN in children might be missed with manifestation of irreversible damage only decades after the true onset, as 50% of subjects with IgAN enter renal replacement treatment before the age of 50 years. In both adults and children the assessment of risk profile is crucial to avoid overtreatment in benign cases or institute a prompt and valid therapy in potentially progressive cases. In case of common risk factors, new therapeutic opportunities tested in adults might be applied to children with the expectation of similar results. If IgAN is the same disease in spite of different clinical profiles in children and adults, an early intervention may be the correct way to prevent progression decades later. On the contrary, if we are dealing with different clinical entities, the treatment in pediatric and in adult settings must be kept apart. This review addresses to report similarities and differences of IgAN across the life periods in order to reason on the application of newly offered treatments over the entire spectrum of this disease or in focused age indications.
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