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Emami A, Nili F, Sotoudeh Anvari M, Salarvand S, Seirafi G. Clinicopathological Features of Hereditary Nephritis in the Iranian Population: Analysis of a 14-Year Survey in Kidney Biopsies From a Large Referral Center. ARCHIVES OF IRANIAN MEDICINE 2024; 27:8-14. [PMID: 38431955 PMCID: PMC10915930 DOI: 10.34172/aim.2024.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 11/08/2023] [Indexed: 03/05/2024]
Abstract
BACKGROUND Hereditary nephritis (HN), including Alport syndrome (AS) and thin basement membrane nephropathy (TBMN), is a rare genetic cause of hematuria. A definitive diagnosis requires electron microscopy (EM). Therefore, the clinical characteristics of these conditions are less known. This study aimed to determine the percentage and clinicopathological features of HN in patients from a referral center in Iran. METHODS We checked kidney biopsy reports from 2007 to 2021 and extracted cases with HN. Fresh specimens of the cases diagnosed in the last two years were stained by immunofluorescence (IF) for collagen type IV alpha chains. EM findings in these cases were re-evaluated and categorized as diffuse glomerular basement membrane (GBM) thinning, definite, and suspicious features of AS. RESULTS We analyzed 3884 pathology reports of kidney biopsies from 2007 to 2021 and identified 210 patients (5.4%) with HN, with a mean age of 13.78±12.42 years old. Hematuria with proteinuria (53.3%), isolated hematuria (44.2%), and proteinuria with hematuria and increased creatinine (2.5%) were found in these patients. The re-evaluation of EM findings revealed GBM thinning, definite, and suspicious findings of AS in 37.5%, 43.8%, and 18.8% cases, respectively. The most common diagnosis in 32 cases after the IF study was X-linked AS (71.9%), and 6.2% of cases were autosomal recessive AS. TBMN and autosomal dominant AS remained the differential diagnoses in 21.9%. CONCLUSION It was found that EM is helpful for the primary diagnosis of patients with definite AS. Immunostaining improves the diagnostic sensitivity for the differentiation of those with suspicious EM findings and determines the inheritance pattern. However, a multidisciplinary approach for a subset of cases is required for the best diagnosis and management.
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Affiliation(s)
- Amir Emami
- Department of Pathology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Nili
- Department of Pathology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Sotoudeh Anvari
- Department of Molecular Pathology, Children Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Samaneh Salarvand
- Department of Pathology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
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Qiu J, Chi H, Gan C, Zhou X, Chen D, Yang Q, Chen Y, Wang M, Yang H, Jiang W, Li Q. A high-impact FN1 variant correlates with fibronectin-mediated glomerulopathy via decreased binding to collagen type IV. Pathology 2023; 55:498-507. [PMID: 36774238 DOI: 10.1016/j.pathol.2022.10.016] [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: 04/11/2022] [Revised: 10/24/2022] [Accepted: 10/31/2022] [Indexed: 01/22/2023]
Abstract
The glomerular basement membrane (GBM) consists of laminins, collagen IV, nidogens, and fibronectin and is essential for filtration barrier integrity in the kidney. Critically, structural and functional abnormalities in the GBM are involved in chronic kidney disease (CKD) occurrence and development. Fibronectin is encoded by FN1 and is essential for podocyte-podocyte and podocyte-matrix interactions. However, disrupted or disordered fibronectin occurs in many kidney diseases. In this study, we identified a novel mutation (c.3415G>A) in FN1 that causes glomerular fibronectin-specific deposition in a gain-of-function manner, that may be associated with thin basement membrane nephropathy (TBMN) and expand the spectrum of phenotypes seen in glomerulopathy with fibronectin deposits (GFND). Our studies confirmed this variant increased fibronectin's ability to bind to integrin, thereby maintaining podocyte adhesion. Also, we hypothesised that TBMN arose as the fibronectin variant exhibited a decreased capacity to bind COL4A3/4. Our study is the first to identify and link this novel pathogenic mutation (c.3415G>A) in FN1 to GFND as well as TBMN, which may broaden the phenotype and mutation spectrums of the FN1 gene. We believe our data will positively impact genetic counselling and prenatal diagnostics for GFND with TBMN and other associated conditions that may be commonly benign conditions in humans, and may not require proteinuria-lowering treatments or renal biopsy.
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Affiliation(s)
- Jiawen Qiu
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Huan Chi
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Chun Gan
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xindi Zhou
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Dan Chen
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Qing Yang
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Yaxi Chen
- Centre for Lipid Research and Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education), Institute for Viral Hepatitis, Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Mo Wang
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Haiping Yang
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Jiang
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
| | - Qiu Li
- Pediatric Research Institute, Department of Nephrology, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child Development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
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Zuckerman JE, Srivastava R. Sporadic Case of Heterozygous X-Linked Alport Syndrome. GLOMERULAR DISEASES 2023; 3:126-131. [PMID: 37901703 PMCID: PMC10601899 DOI: 10.1159/000530994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 05/02/2023] [Indexed: 10/31/2023]
Abstract
Alport syndrome is a genetically and phenotypically heterogeneous disorder that can be transmitted in an X-linked, autosomal recessive, or autosomal dominant fashion and can affect glomerular, cochlear, and ocular basement membranes. The disorder results from mutations in the collagen IV genes COL4A5 (X chromosome), COL4A3, and COL4A4. Alport patients are at lifetime risk for kidney failure, sensorineural deafness, and ocular abnormalities. Males with Alport syndrome typically present with severe phenotype with progression to end-stage kidney disease and/or sensorineural deafness and eye changes. Females generally having less severe presentation and diagnosis of X-linked Alport syndrome are generally not considered. Here, we report a case of a 3-year-old girl with gross hematuria, proteinuria, and chronic kidney disease who was found to have features of Alport syndrome on kidney biopsy and a sporadic heterozygous pathogenic COL4A5 deletion on molecular testing. This case report emphasizes the importance of kidney biopsy and molecular testing in the work up of pediatric patients with hematuria, proteinuria, and/or chronic kidney disease. It is also a poignant illustration that females with heterozygous X-linked COL4A5 mutations are often affected patients. It further illustrates the phenomenon of sporadic occurrence of genetic kidney disease in the absence of family history of kidney disease.
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Affiliation(s)
- Jonathan E Zuckerman
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Rachana Srivastava
- Department of Pediatric Nephrology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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