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Mabillard H, Ryan R, Tzoumas N, Gear S, Sayer JA. Explaining Alport syndrome-lessons from the adult nephrology clinic. J Rare Dis (Berlin) 2024; 3:14. [PMID: 38745975 PMCID: PMC11088994 DOI: 10.1007/s44162-024-00036-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 02/15/2024] [Indexed: 05/16/2024]
Abstract
Alport syndrome is a genetic kidney disease that causes worsening of kidney function over time, often progressing to kidney failure. Some types of Alport syndrome cause other symptoms and signs, including hearing loss and eye abnormalities. Research now indicates that Alport syndrome (autosomal dominant inheritance) is the most common form. Alport syndrome can have X-linked or a rare form of autosomal recessive inheritance. Traditionally, a kidney biopsy was used to diagnose Alport syndrome, but genetic testing provides a more precise and less invasive means of diagnosis and reveals the underlying pattern of inheritance. At present, there are no specific curative treatments for Alport syndrome however there is a strong international effort in pursuit of future therapies. Currently, angiotensin-converting enzyme inhibitors (ACEi), or an angiotensin receptor blocker (ARB) if a patient cannot tolerate an ACEi, slow down the progression of kidney disease and can delay the onset of kidney failure by years. There are other potential treatments in research that potentially can help delay the onset of kidney issues. Early treatment of patients and identification of their at-risk relatives is a priority. People living with Alport syndrome and their doctors now benefit from an active international research community working on translating further treatments into clinical practice and providing up-to-date clinical guidelines.
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Affiliation(s)
- Holly Mabillard
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
| | - Rebecca Ryan
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
| | - Nik Tzoumas
- Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
- Sunderland Eye Infirmary, Sunderland, UK
| | - Susie Gear
- Alport UK, Cirencester, Gloucestershire, UK
| | - John A. Sayer
- Renal Services, Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Central Parkway, Newcastle Upon Tyne, UK
- NIHR Newcastle Biomedical Research Centre, Newcastle Upon Tyne, UK
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Gao Y, Yuan L, Yuan J, Yang Y, Wang J, Chen Y, Zhang H, Ai Y, Deng H. Identification of COL4A4 variants in Chinese patients with familial hematuria. Front Genet 2023; 13:1064491. [PMID: 36699462 PMCID: PMC9868811 DOI: 10.3389/fgene.2022.1064491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 12/15/2022] [Indexed: 01/11/2023] Open
Abstract
Background: Benign familial hematuria and Alport syndrome are common causes of familial hematuria among children and young adults, which are attributable to variants in the collagen type IV alpha chain genes, COL4A3, COL4A4, or COL4A5. The study was conducted to identify the underlying genetic causes in patients with familial hematuria. Methods: Two unrelated Han-Chinese pedigrees with familial hematuria were recruited for this study. Whole exome sequencing was combined with in silico analysis to identify potential genetic variants, followed by variant confirmation by Sanger sequencing. Reverse transcription, PCR, and Sanger sequencing were performed to evaluate the effect of the detected splicing variant on mRNA splicing. Results: A novel heterozygous splicing c.595-1G>A variant and a known heterozygous c.1715G>C variant in the collagen type IV alpha 4 chain gene (COL4A4) were identified and confirmed in patients of pedigree 1 and pedigree 2, respectively. Complementary DNA analysis indicated this splicing variant could abolish the canonical splice acceptor site and cause a single nucleotide deletion of exon 10, which was predicted to produce a truncated protein. Conclusions: The two COL4A4 variants, c.595-1G>A variant and c.1715G>C (p.Gly572Ala) variant, were identified as the genetic etiologies of two families with familial hematuria, respectively. Our study broadened the variant spectrum of the COL4A4 gene and explained the possible pathogenesis, which will benefit clinical management and genetic counseling.
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Affiliation(s)
- Yanan Gao
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China,Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Lamei Yuan
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China,Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China,Disease Genome Research Center, Central South University, Changsha, China
| | - Jinzhong Yuan
- Department of Nephrology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yan Yang
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Jiangang Wang
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yong Chen
- National Health Committee Key Laboratory of Birth Defects for Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, China
| | - Hao Zhang
- Department of Nephrology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Yinze Ai
- Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Hao Deng
- Health Management Center, The Third Xiangya Hospital, Central South University, Changsha, China,Center for Experimental Medicine, The Third Xiangya Hospital, Central South University, Changsha, China,Disease Genome Research Center, Central South University, Changsha, China,*Correspondence: Hao Deng,
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Daga S, Ding J, Deltas C, Savige J, Lipska-Ziętkiewicz BS, Hoefele J, Flinter F, Gale DP, Aksenova M, Kai H, Perin L, Barua M, Torra R, Miner JH, Massella L, Ljubanović DG, Lennon R, Weinstock AB, Knebelmann B, Cerkauskaite A, Gear S, Gross O, Turner AN, Baldassarri M, Pinto AM, Renieri A. The 2019 and 2021 International Workshops on Alport Syndrome. Eur J Hum Genet 2022; 30:507-16. [PMID: 35260866 DOI: 10.1038/s41431-022-01075-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Kumar R, Keskinyan V, Stangl MC, Lane BM, Buckley AF, Barisoni L, Howell DN, Gbadegesin RA. Case Report: Unusual Aggregation of Different Glomerulopathies in a Family Resolved by Genetic Testing and Reverse Phenotyping. Front Pediatr 2022; 10:826330. [PMID: 35295700 PMCID: PMC8918647 DOI: 10.3389/fped.2022.826330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/20/2022] [Indexed: 11/24/2022] Open
Abstract
Glomerular diseases (GDs) are a major cause of chronic kidney disease in children. The conventional approach to diagnosis of GDs includes clinical evaluation and, in most cases, kidney biopsy to make a definitive diagnosis. However, in many cases, clinical presentations of different GDs can overlap, leading to uncertainty in diagnosis and management even after renal biopsy. In this report, we identify a family with clinical diagnoses of postinfectious glomerulonephritis and IgA nephropathy in a parent and two children. Renal biopsies were initially inconclusive; however, genetic testing showed that the two individuals diagnosed at different points with IgA nephropathy carried novel segregating pathogenic variants in COL4A5 gene. We were only able to make the final diagnoses in each of the family members after genetic testing and reverse phenotyping. This case highlights the utility of genetic testing and reverse phenotyping in resolving clinical diagnosis in families with unusual constellations of different glomerulopathies. We propose that clustering of different glomerular disease phenotypes in a family should be an indication for genetic testing followed by reverse phenotyping.
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Affiliation(s)
- Reeti Kumar
- Division of Nephrology, Department of Pediatrics, Duke University Medical Center, Durham, NC, United States
| | - Vahakn Keskinyan
- Division of Nephrology, Department of Pediatrics, Duke University Medical Center, Durham, NC, United States
| | - Megan Chryst Stangl
- Division of Nephrology, Department of Pediatrics, Duke University Medical Center, Durham, NC, United States
| | - Brandon M Lane
- Division of Nephrology, Department of Pediatrics, Duke University Medical Center, Durham, NC, United States
| | - Anne F Buckley
- Division of Renal Pathology, Department of Pathology, Duke University Medical Center, Durham, NC, United States
| | - Laura Barisoni
- Division of Renal Pathology, Department of Pathology, Duke University Medical Center, Durham, NC, United States
| | - David N Howell
- Division of Renal Pathology, Department of Pathology, Duke University Medical Center, Durham, NC, United States
| | - Rasheed A Gbadegesin
- Division of Nephrology, Department of Pediatrics, Duke University Medical Center, Durham, NC, United States
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