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Choi YW, Kim YG, Song MY, Moon JY, Jeong KH, Lee TW, Ihm CG, Park KS, Lee SH. Potential urine proteomics biomarkers for primary nephrotic syndrome. Clin Proteomics 2017; 14:18. [PMID: 28522940 PMCID: PMC5434615 DOI: 10.1186/s12014-017-9153-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 05/06/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Nephrotic syndrome (NS) is a nonspecific kidney disorder, commonly caused by minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), and membranous nephropathy (MN). Here we analyzed urinary protein profiles, aiming to discover disease-specific biomarkers of these three common diseases in NS. METHODS Sixteen urine samples were collected from patients with biopsy-proven NS and healthy controls. After removal of high-abundance proteins, the urinary protein profile was analyzed by LC-MS/MS to generate a discovery set. For validation, ELISA was used to analyze the selected proteins in 61 urine samples. RESULTS The discovery set included 228 urine proteins, of which 22 proteins were differently expressed in MCD, MN, and FSGS. Among these, C9, CD14, and SERPINA1 were validated by ELISA. All three proteins were elevated in MCD, MN, and FSGS groups compared with in IgA nephropathy and healthy controls. When a regression model was applied, receiver operating characteristic analysis clearly discriminated MCD from the other causative diseases in NS. CONCLUSIONS We developed a disease-specific protein panel that discriminated between three main causes of NS. Through this pilot study, we suggest that urine proteomics could be a non-invasive and clinically available tool to discriminate MCD from MN and FSGS.
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Affiliation(s)
- Young Wook Choi
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University School of Medicine, 892 Dongnam-ro, Gangdong-gu, Seoul, Korea
| | - Yang Gyun Kim
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University School of Medicine, 892 Dongnam-ro, Gangdong-gu, Seoul, Korea
| | - Min-Young Song
- Department of Physiology, Kyung Hee University School of Medicine, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, Korea
| | - Ju-Young Moon
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University School of Medicine, 892 Dongnam-ro, Gangdong-gu, Seoul, Korea
| | - Kyung-Hwan Jeong
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University School of Medicine, 892 Dongnam-ro, Gangdong-gu, Seoul, Korea
| | - Tae-Won Lee
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University School of Medicine, 892 Dongnam-ro, Gangdong-gu, Seoul, Korea
| | - Chun-Gyoo Ihm
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University School of Medicine, 892 Dongnam-ro, Gangdong-gu, Seoul, Korea
| | - Kang-Sik Park
- Department of Physiology, Kyung Hee University School of Medicine, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul, Korea
| | - Sang-Ho Lee
- Division of Nephrology, Department of Internal Medicine, Kyung Hee University School of Medicine, 892 Dongnam-ro, Gangdong-gu, Seoul, Korea
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Chittoor G, Haack K, Mehta NR, Laston S, Cole SA, Comuzzie AG, Butte NF, Voruganti VS. Genetic variation underlying renal uric acid excretion in Hispanic children: the Viva La Familia Study. BMC MEDICAL GENETICS 2017; 18:6. [PMID: 28095793 PMCID: PMC5240212 DOI: 10.1186/s12881-016-0366-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 12/30/2016] [Indexed: 01/01/2023]
Abstract
Background Reduced renal excretion of uric acid plays a significant role in the development of hyperuricemia and gout in adults. Hyperuricemia has been associated with chronic kidney disease and cardiovascular disease in children and adults. There are limited genome-wide association studies associating genetic polymorphisms with renal urate excretion measures. Therefore, we investigated the genetic factors that influence the excretion of uric acid and related indices in 768 Hispanic children of the Viva La Familia Study. Methods We performed a genome-wide association analysis for 24-h urinary excretion measures such as urinary uric acid/urinary creatinine ratio, uric acid clearance, fractional excretion of uric acid, and glomerular load of uric acid in SOLAR, while accounting for non-independence among family members. Results All renal urate excretion measures were significantly heritable (p <2 × 10−6) and ranged from 0.41 to 0.74. Empirical threshold for genome-wide significance was set at p <1 × 10−7. We observed a strong association (p < 8 × 10−8) of uric acid clearance with a single nucleotide polymorphism (SNP) in zinc finger protein 446 (ZNF446) (rs2033711 (A/G), MAF: 0.30). The minor allele (G) was associated with increased uric acid clearance. Also, we found suggestive associations of uric acid clearance with SNPs in ZNF324, ZNF584, and ZNF132 (in a 72 kb region of 19q13; p <1 × 10−6, MAFs: 0.28–0.31). Conclusion For the first time, we showed the importance of 19q13 region in the regulation of renal urate excretion in Hispanic children. Our findings indicate differences in inherent genetic architecture and shared environmental risk factors between our cohort and other pediatric and adult populations. Electronic supplementary material The online version of this article (doi:10.1186/s12881-016-0366-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Geetha Chittoor
- Department of Nutrition and UNC Nutrition Research Institute, University of North Carolina at Chapel Hill, 500 Laureate Way, Kannapolis, NC, 28081, USA
| | - Karin Haack
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Nitesh R Mehta
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Sandra Laston
- South Texas Diabetes and Obesity Institute, School of Medicine, University of Texas Rio Grande Valley, Brownsville, TX, USA
| | - Shelley A Cole
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Anthony G Comuzzie
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Nancy F Butte
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - V Saroja Voruganti
- Department of Nutrition and UNC Nutrition Research Institute, University of North Carolina at Chapel Hill, 500 Laureate Way, Kannapolis, NC, 28081, USA.
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Zhang YM, Gu QH, Huang J, Qu Z, Wang X, Meng LQ, Wang F, Liu G, Cui Z, Zhao MH. Clinical Significance of IgM and C3 Glomerular Deposition in Primary Focal Segmental Glomerulosclerosis. Clin J Am Soc Nephrol 2016; 11:1582-1589. [PMID: 27340287 PMCID: PMC5012474 DOI: 10.2215/cjn.01190216] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 05/26/2016] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND OBJECTIVES Glomerular IgM deposition is commonly shown in primary FSGS and sometimes accompanied by C3 deposition. Clinical presentation and treatment outcomes of these patients are not investigated in detail. DESIGN, SETTING, PARTICIPANTS, &MEASUREMENTS One hundred six consecutive patients with biopsy-proven primary FSGS from 2004 to 2014 were enrolled retrospectively. Clinical features and treatment outcomes were compared between patients with and without IgM/C3 deposition. RESULTS Fifty-eight (54.7%) patients presented with IgM glomerular deposition on sclerotic segments. C3 and C1q depositions were shown exclusively in patients with IgM deposition (34.5% versus 0.0%; P<0.001 and 8.6% versus 0.0%; P=0.04, respectively). Patients with IgM deposition were younger (median; range: 24.5; 18.8-39.0 versus 46.5; 26.0-64.0 years old; P=0.001), had higher level of serum IgM (142.5; 96.3-206.0 versus 107.0; 71.0-140.0 mg/dl; P=0.01), and had higher level of eGFR (median; range 97.7; 48.0-135.8 versus 62.1; 33.7-93.9 ml/min per 1.73 m(2); P=0.01) at the time of kidney biopsy. The percentage of sclerosis lesions was significantly higher in patients with C3 deposition (median; range: 21.7%; 15.3%-31.1% versus 9.2%; 6.6%-20.0%; P=0.002). Although patients received comparable immunosuppressive treatments during 58.9 (29.5-81.1) months of follow-up, a significantly higher prevalence of refractory cases (no response or steroid dependent) occurred in patients with combined IgM and C3 deposition compared with patients with IgM deposition alone or without IgM deposition (58.8% versus 22.2% versus 15.6%, respectively; P=0.004). Multivariate analysis identified combined IgM and C3 deposition (odds ratio, 11.32; 95% confidence interval, 2.26 to 56.65; P=0.003) as an independent risk factor for refractory patients; 19 of 98 patients developed renal dysfunction when their serum creatinine levels increased >30% from baseline and reached >1.5 mg/dl. Combined IgM and C3 deposition (hazard ratio, 5.67; 95% confidence interval, 1.34 to 23.84; P=0.02) was identified as an independent risk factor for renal dysfunction. CONCLUSIONS Patients with primary FSGS and IgM and C3 deposition showed unfavorable therapeutic responses and worse renal outcomes, which indicate that IgM and C3 deposition might involve disease progression via complement activation.
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Affiliation(s)
- Yi-miao Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Qiu-hua Gu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Jing Huang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Zhen Qu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Xin Wang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Li-qiang Meng
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Fang Wang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Gang Liu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Zhao Cui
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
| | - Ming-hui Zhao
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China
- Institute of Nephrology, Peking University, Beijing, China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China
- Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, China; and
- Peking-Tsinghua Center for Life Sciences, Beijing, China
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Saleem MA. New developments in steroid-resistant nephrotic syndrome. Pediatr Nephrol 2013; 28:699-709. [PMID: 22782578 DOI: 10.1007/s00467-012-2239-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 05/04/2012] [Accepted: 05/04/2012] [Indexed: 12/20/2022]
Abstract
Nephrotic syndrome is a disorder of the glomerular filtration barrier, a highly specialised tri-layer structure with unique functional properties. Recent advances emanating from the field of molecular genetics have revealed the podocyte as probably the central player in the control of glomerular filtration. More specifically, the cell-cell junction between adjacent podocyte foot processes, namely, the slit diaphragm, has been revealed to be made up of a sophisticated multi-protein complex which dynamically controls foot process architecture via signalling to the actin cytoskeleton. Key genes that have been identified from the study of inherited nephrotic syndromes include those encoding nephrin, podocin, TRPC6 (transient receptor potential canonical channel-6) and α-actinin-4, and more remain to be found. It is now possible to identify genetic causes underlying a proportion of nephrotic syndromes presenting at any age. The next big challenge for clinicians and researchers is to translate the molecular information learnt into the understanding of acquired, non-inherited forms of the disease and to guide therapeutic options. In this regard several exciting advances have been made, both in understanding the molecular mechanisms of current therapies and in revealing circulating plasma factors and the molecular pathways they trigger in the podocyte, that could be targeted by novel therapies.
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Affiliation(s)
- Moin A Saleem
- Academic Renal Unit, Learning and Research Building, Southmead Hospital, Bristol, UK.
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5
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Gadegbeku CA, Gipson DS, Holzman LB, Ojo AO, Song PXK, Barisoni L, Sampson MG, Kopp JB, Lemley KV, Nelson PJ, Lienczewski CC, Adler SG, Appel GB, Cattran DC, Choi MJ, Contreras G, Dell KM, Fervenza FC, Gibson KL, Greenbaum LA, Hernandez JD, Hewitt SM, Hingorani SR, Hladunewich M, Hogan MC, Hogan SL, Kaskel FJ, Lieske JC, Meyers KEC, Nachman PH, Nast CC, Neu AM, Reich HN, Sedor JR, Sethna CB, Trachtman H, Tuttle KR, Zhdanova O, Zilleruelo GE, Kretzler M. Design of the Nephrotic Syndrome Study Network (NEPTUNE) to evaluate primary glomerular nephropathy by a multidisciplinary approach. Kidney Int 2013; 83:749-56. [PMID: 23325076 PMCID: PMC3612359 DOI: 10.1038/ki.2012.428] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The Nephrotic Syndrome Study Network (NEPTUNE) is a North American multicenter collaborative consortium established to develop a translational research infrastructure for nephrotic syndrome. This includes a longitudinal observational cohort study, a pilot and ancillary study program, a training program, and a patient contact registry. NEPTUNE will enroll 450 adults and children with minimal change disease, focal segmental glomerulosclerosis, and membranous nephropathy for detailed clinical, histopathological, and molecular phenotyping at the time of clinically indicated renal biopsy. Initial visits will include an extensive clinical history, physical examination, collection of urine, blood and renal tissue samples, and assessments of quality of life and patient-reported outcomes. Follow-up history, physical measures, urine and blood samples, and questionnaires will be obtained every 4 months in the first year and biannually, thereafter. Molecular profiles and gene expression data will be linked to phenotypic, genetic, and digitalized histological data for comprehensive analyses using systems biology approaches. Analytical strategies were designed to transform descriptive information to mechanistic disease classification for nephrotic syndrome and to identify clinical, histological, and genomic disease predictors. Thus, understanding the complexity of the disease pathogenesis will guide further investigation for targeted therapeutic strategies.
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Nishino T, Sasaki N, Nagasaki KI, Ahmad Z, Agui T. Genetic background strongly influences the severity of glomerulosclerosis in mice. J Vet Med Sci 2010; 72:1313-8. [PMID: 20484839 DOI: 10.1292/jvms.10-0144] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ICGN mouse strain is a glomerulosclerosis (GS) model that shows characteristic proteinuria, podocyte morphological abnormalities and increased extracellular matrix accumulation in the glomeruli, which are the final common pathology associated with a variety of kidney diseases leading to end-stage renal failure. Previously, we performed a quantitative trait locus (QTL) analysis to identify the causative genes for GS in ICGN mice and found the deletion mutation of the tensin2 (Tns2) gene that creates both a premature stop codon and dramatically decreases mRNA expression levels within the region of the major QTL (this mutation was designated Tns2(nep)). The severity of GS varies considerably in humans and other animals, indicating the influence of several genes controlling the disease phenotype. In this study, to identify the modifier/resistant gene(s) for GS, we produced congenic strains carrying the Tns2(nep) mutation on the C57BL/6J (B6) genetic background and analyzed GS severity. Interestingly, the B6 congenic mice exhibited milder phenotypes than the ICGN strain mice. The results suggest that B6 mice have a modifier(s) of GS resistance. Therefore, identification of the modifier loci in B6 mice will provide important new information regarding gene interactions controlling GS.
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Affiliation(s)
- Tomohiro Nishino
- Laboratory of Laboratory Animal Science and Medicine, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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8
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Yang HC, Fogo AB. 'Idiopathic' FSGS: an increasingly obsolete diagnosis? Nephrol Dial Transplant 2010; 25:654-6. [PMID: 20083472 DOI: 10.1093/ndt/gfp750] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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9
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Ijpelaar DHT, Schulz A, Aben J, van der Wal A, Bruijn JA, Kreutz R, de Heer E. Genetic predisposition for glomerulonephritis-induced glomerulosclerosis in rats is linked to chromosome 1. Physiol Genomics 2008; 35:173-81. [PMID: 18682577 DOI: 10.1152/physiolgenomics.00268.2007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Genetic factors influence renal disease progression, and several loci have been linked to the spontaneous development of proteinuria and glomerulosclerosis in animal models. However, the role of genetic susceptibility in glomerulonephritis-induced progressive glomerulosclerosis is unknown. In a rat model of mesangial proliferative glomerulonephritis, anti-Thy-1 glomerulonephritis (antiThy1GN), Lewis/Maastricht (Lew/Maa) rats exhibit progression to glomerulosclerosis, whereas in genetically related Lewis/Møllegard (Lew/Moll) rats, glomerular lesions are repaired within 3 wk. The genetic factors underlying this strain-related difference are not known. To identify novel quantitative trait loci (QTL) involved in progression or repair in Lewis rats, 145 female backcross rats [F1(Lew/Maa x Lew/Moll) x Lew/Maa] were studied. After induction of antiThy1GN proteinuria, we determined mesangial activation, the percentage of microaneurysms, and the glomerular damage score for each animal; a genome scan using 187 microsatellite markers was performed. QTL mapping revealed a significant QTL for glomerular damage score on chromosome 1 with a logarithm of odds (LOD) score of 3.9. Homozygosity for Lew/Maa DNA in this region was associated with a higher percentage of damaged glomeruli on day 21. Furthermore, suggestive linkage was found for the percentage of glomeruli with microaneurysms on day 3 on chromosome 1, 6, and 11; for mesangial activation on day 7 on chromosome 18, while proteinuria was suggestively linked to chromosome 5 (day 0), 4 (day 3), and 6 (day 7). This study identifies a QTL on rat chromosome 1 that is significantly linked to progressive glomerulosclerosis after acute glomerulonephritis.
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10
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Winn MP. 2007 Young Investigator Award: TRP'ing into a new era for glomerular disease. J Am Soc Nephrol 2008; 19:1071-5. [PMID: 18434567 DOI: 10.1681/asn.2007121292] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
FSGS is a pathologic lesion that frequently causes the nephrotic syndrome and ensuing renal failure. The cause remains unknown in the majority of individuals; however, in the past two decades, rare familial forms have been identified. It has been suggested that known genetic causes of the hereditary form of this disease account for upwards of 18% of cases. Mutations in five genes have been found to cause inherited nephrotic syndromes and FSGS. In this article, I discuss the phenotypic characteristics of hereditary FSGS and the transient receptor potential cation channel 6 (TRPC6) protein, which is the genetic impetus for an autosomal dominant form of FSGS. The TRP channels have been implicated in varied biologic functions such as mechanosensation, ion homeostasis, cell growth, and phospholipase C-dependent calcium entry into cells. The mutated ion channel causes an increase in calcium transients. Current evidence also suggests that blocking TRPC6 channels may be of therapeutic benefit in idiopathic FSGS, a disease with a generally poor prognosis. Preliminary experiments reveal that the commonly used immunosuppressive agent FK-506 can inhibit TRPC6 activity in vivo. This creates the intriguing possibility that blocking TRPC6 channels within the podocyte may translate into long-lasting clinical benefits in patients with FSGS.
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Affiliation(s)
- Michelle P Winn
- Department of Medicine and Center for Human Genetics, Duke University Medical Center, Duke Box 2903, Durham, NC 27705, USA.
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11
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Voskarides K, Pierides A, Deltas C. COL4A3/COL4A4 mutations link familial hematuria and focal segmental glomerulosclerosis. glomerular epithelium destruction via basement membrane thinning? Connect Tissue Res 2008; 49:283-8. [PMID: 18661361 DOI: 10.1080/03008200802148280] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The recent description of multiple gene defects in hereditary podocytopathies and in hereditary glomerular basement membrane diseases has dramatically improved the current state of our knowledge on the renal glomerular filtration barrier. Recently described mutations in collagen IV and laminin in patients with hematuria and severe nephrotic syndrome add to other experimental data supporting the hypothesis that the glomerular basement membrane (GBM) may also have a significant role in protein filtration, a function previously attributed exclusively to the podocytes. Collagen IV heterozygous mutations were thought to cause only a mild form of renal disease (thin basement membrane nephropathy--TBMN). However, data from our laboratory show that many patients who carry such mutations may later on in life develop focal and segmental glomerulosclerosis, on top of the TBMN and the microscopic hematuria, a situation that frequently progresses to chronic renal failure or even end-stage renal disease. The role of unknown modifier genes may explain the heterogeneity of symptoms in TBMN and other glomerular diseases and in particular the selected development of chronic renal failure. The molecular communication between GBM and podocytes may also be a key factor in the search for these major genetic modifiers while their understanding may improve novel drug design for glomerular diseases.
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12
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Pollak MR, Alexander MP, Henderson JM. A case of familial kidney disease. Clin J Am Soc Nephrol 2007; 2:1367-74. [PMID: 17942774 DOI: 10.2215/cjn.02040507] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Martin R Pollak
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.
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13
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Barisoni L, Schnaper HW, Kopp JB. A proposed taxonomy for the podocytopathies: a reassessment of the primary nephrotic diseases. Clin J Am Soc Nephrol 2007; 2:529-42. [PMID: 17699461 DOI: 10.2215/cjn.04121206] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A spectrum of proteinuric glomerular diseases results from podocyte abnormalities. The understanding of these podocytopathies has greatly expanded in recent years, particularly with the discovery of more than a dozen genetic mutations that are associated with loss of podocyte functional integrity. It is apparent that classification of the podocytopathies on the basis of morphology alone is inadequate to capture fully the complexity of these disorders. Herein is proposed a taxonomy for the podocytopathies that classifies along two dimensions: Histopathology, including podocyte phenotype and glomerular morphology (minimal-change nephropathy, focal segmental glomerulosclerosis, diffuse mesangial sclerosis, and collapsing glomerulopathy), and etiology (idiopathic, genetic, and reactive forms). A more complete understanding of the similarities and differences among podocyte diseases will help the renal pathologist and the nephrologist communicate more effectively about the diagnosis; this in turn will help the nephrologist provide more accurate prognostic information and select the optimal therapy for these often problematic diseases. It is proposed that final diagnosis of the podocytopathies should result from close collaboration between renal pathologists and nephrologists and should whenever possible include three elements: Morphologic entity, etiologic form, and specific pathogenic mechanism or association.
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Affiliation(s)
- Laura Barisoni
- Department of Pathology, New York University School of Medicine, New York, New York, USA
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Mukerji N, Damodaran TV, Winn MP. TRPC6 and FSGS: the latest TRP channelopathy. Biochim Biophys Acta Mol Basis Dis 2007; 1772:859-68. [PMID: 17459670 DOI: 10.1016/j.bbadis.2007.03.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Revised: 03/12/2007] [Accepted: 03/13/2007] [Indexed: 01/12/2023]
Abstract
Focal and segmental glomerulosclerosis (FSGS) is a common cause of nephrotic syndrome in children and adults throughout the world. In the past 50 years, significant advances have been made in the identification and characterization of familial forms of nephrotic syndrome and FSGS. Resultant to these pursuits, several podocyte structural proteins such as nephrin, podocin, alpha-actinin 4 (ACTN4), and CD2-associated protein (CD2AP) have emerged to provide critical insight into the pathogenesis of hereditary nephrotic syndromes. The latest advance in familial FSGS has been the discovery of a mutant form of canonical transient receptor potential cation channel 6 (TRPC6), which causes an increase in calcium transients and essentially a gain of function in this cation channel located on the podocyte cell membrane. The TRP ion channel family is a diverse group of cation channels united by a common primary structure which contains six membrane-spanning domains, with both carboxy and amino termini located intracellularly. TRP channels are unique in their ability to activate independently of membrane depolarization. TRPC6 channels have been shown to be activated via phospholipase C stimulation. The mechanisms by which mutant TRPC6 causes an increase in intracellular calcium and leads to glomerulosclerosis are unknown. Mutant TRPC6 may affect critical interactions with the aforementioned podocyte structural proteins, leading to abnormalities in the slit diaphragm or podocyte foot processes. Mutant TRPC6 may also amplify injurious signals mediated by Ang II, a common final pathway of podocyte apoptosis in various mammalian species. Current evidence also suggests that blocking TRPC6 channels may be of therapeutic benefit in idiopathic FSGS, a disease with a generally poor prognosis. Preliminary experiments reveal the commonly used immunosuppressive agent FK-506 can inhibit TRPC6 activity in vivo. This creates the exciting possibility that blocking TRPC6 channels within the podocyte may translate into long-lasting clinical benefits in patients with FSGS.
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Affiliation(s)
- Nirvan Mukerji
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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15
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He N, Zahirieh A, Mei Y, Lee B, Senthilnathan S, Wong B, Mucha B, Hildebrandt F, Cole DE, Cattran D, Pei Y. Recessive NPHS2 (Podocin) mutations are rare in adult-onset idiopathic focal segmental glomerulosclerosis. Clin J Am Soc Nephrol 2006; 2:31-7. [PMID: 17699384 DOI: 10.2215/cjn.02690806] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Recessive NPHS2 (podocin) mutations account for up to approximately 30% of steroid-resistant idiopathic FSGS in children and are associated with a reduced risk for disease recurrence after renal transplantation. R229Q, a missense variant that is present in 3.6% of the white population, has been implicated as a common disease-causing mutation. Given these clinical implications, we examined the role of NPHS2 mutations in a cohort of patients with adult-onset FSGS. We used denaturing HPLC to screen for heterozygous and homozygous gene variants in PCR-amplified DNA fragments that contained all exons and splice junctions of NPHS2. Bidirectional sequencing was performed to define all of the gene variants detected. With the use of the denaturing HPLC in a single-blind pilot study, 40 of 43 known NPHS2 mutations were detected from 22 pediatric patients with FSGS to establish a test sensitivity of 93%. This screen then was applied to 87 adult patients with idiopathic FSGS (15 steroid-sensitive, 63 steroid-resistant, and nine familial cases). In this latter cohort, compound heterozygous mutations were detected only in one patient with steroid-sensitive FSGS (R229Q and Q285fsX302) and no homozygous mutations. Overall, R229Q accounted for eight (80%) of ten of the putative mutant alleles that were detected in the study cohort. Contrary to the pediatric experience, recessive NPHS2 mutations are rare in this study population, suggesting that the pathogenesis of FSGS in adults may differ from that in children. These data do not support R229Q as a disease-causing mutation for steroid-resistant FSGS.
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Affiliation(s)
- Ning He
- Division of Nephrology, Toronto General Hospital, University Health Network and University of Toronto, Toronto, Ontario, Canada
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Kim EH, Lee CH, Hyun BH, Suh JG, Oh YS, Namikawa T, Ishikawa A. Quantitative trait loci for proteinuria in the focal glomerulosclerosis mouse model. Mamm Genome 2005; 16:242-50. [PMID: 15965785 DOI: 10.1007/s00335-004-3023-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Accepted: 01/06/2005] [Indexed: 10/25/2022]
Abstract
The FGS/Kist strain of mice, a new animal model for focal glomerulosclerosis (FGS) in humans, was previously established by recurrent selection for high proteinuria, which is a principal marker of FGS, from descendants of CBA/Nga and RFM/Nga strains. We performed a genome-wide scan for quantitative trait loci (QTLs) affecting proteinuria in a population of 356 backcross progeny derived from a cross between FGS/Kist and the standard normal strain, C57BL/6J. Five proteinuria QTLs (Ptnu1-5) were detected at the genome-wide 5% or less level. Ptnu1 and Ptnu2, located on Chromosomes (Chrs) 8 and 17, respectively, had main effects on proteinuria and also interacted epistatically with each other. However, Ptnu3 on Chr 9 and Ptnu4 and Ptnu5 both on Chr 15 had epistatic interaction effects only. Except for the epistatic interaction effect of Ptnu4 and Ptnu5, all alleles derived from FGS/Kist were responsible for the high proteinuria. These results indicated that the genetic control of proteinuria is complex and the identified QTLs may provide new insights into the pathogenesis of FGS in mice as well as in humans.
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Affiliation(s)
- Eun-Hee Kim
- Laboratory of Animal Genetics, Division of Applied Genetics and Physiology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
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17
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Winn MP, Conlon PJ, Lynn KL, Farrington MK, Creazzo T, Hawkins AF, Daskalakis N, Kwan SY, Ebersviller S, Burchette JL, Pericak-Vance MA, Howell DN, Vance JM, Rosenberg PB. A mutation in the TRPC6 cation channel causes familial focal segmental glomerulosclerosis. Science 2005; 308:1801-4. [PMID: 15879175 DOI: 10.1126/science.1106215] [Citation(s) in RCA: 799] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Focal and segmental glomerulosclerosis (FSGS) is a kidney disorder of unknown etiology, and up to 20% of patients on dialysis have been diagnosed with it. Here we show that a large family with hereditary FSGS carries a missense mutation in the TRPC6 gene on chromosome 11q, encoding the ion-channel protein transient receptor potential cation channel 6 (TRPC6). The proline-to-glutamine substitution at position 112, which occurs in a highly conserved region of the protein, enhances TRPC6-mediated calcium signals in response to agonists such as angiotensin II and appears to alter the intracellular distribution of TRPC6 protein. Previous work has emphasized the importance of cytoskeletal and structural proteins in proteinuric kidney diseases. Our findings suggest an alternative mechanism for the pathogenesis of glomerular disease.
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MESH Headings
- Amino Acid Substitution
- Angiotensin II/metabolism
- Angiotensin II/pharmacology
- Calcium/metabolism
- Calcium Channels/chemistry
- Calcium Channels/genetics
- Calcium Channels/metabolism
- Calcium Signaling
- Carbachol/pharmacology
- Cell Line
- Cell Membrane/metabolism
- Chromosomes, Human, Pair 11/genetics
- Exons
- Female
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- Glomerulosclerosis, Focal Segmental/genetics
- Haplotypes
- Humans
- Kidney/metabolism
- Kidney Glomerulus/metabolism
- Kidney Tubules/metabolism
- Male
- Mutation, Missense
- Patch-Clamp Techniques
- Pedigree
- Receptor, Angiotensin, Type 1/genetics
- Receptor, Angiotensin, Type 1/metabolism
- Sequence Analysis, DNA
- Sodium/metabolism
- TRPC Cation Channels
- TRPC6 Cation Channel
- Transfection
- Uridine Triphosphate/metabolism
- Uridine Triphosphate/pharmacology
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Affiliation(s)
- Michelle P Winn
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
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18
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Orloff MS, Iyengar SK, Winkler CA, Goddard KAB, Dart RA, Ahuja TS, Mokrzycki M, Briggs WA, Korbet SM, Kimmel PL, Simon EE, Trachtman H, Vlahov D, Michel DM, Berns JS, Smith MC, Schelling JR, Sedor JR, Kopp JB. Variants in the Wilms' tumor gene are associated with focal segmental glomerulosclerosis in the African American population. Physiol Genomics 2005; 21:212-21. [PMID: 15687485 DOI: 10.1152/physiolgenomics.00201.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Wilms' tumor gene (WT1) is important for nephrogenesis and gonadal growth. WT1 mutations cause Denys-Drash and Frasier syndromes, which are characterized by glomerular scarring. To test whether genetic variations in WT1 and WIT1 (gene immediately 5' to WT1) associate with focal segmental glomerulosclerosis (FSGS), patients with biopsy-proven idiopathic and HIV-1-associated FSGS were enrolled in a multicenter study. We genotyped SNP rs6508 located in WIT1 exon 1, three SNPs (rs2301250, rs2301252, rs2301254) in the promoter shared by WT1 and WIT1, rs2234590 in exon 6, rs2234591 in intron 6, rs16754 in exon 7, and rs1799937 in intron 9 of WT1. Cases (n = 218) and controls (n = 281) were compared in the African American population. Stratification by HIV-1 infection status showed that SNPs rs6508, rs2301254, and rs1799937 were significantly associated with FSGS [rs6508 odds ratio (OR) 1.82, P = 0.006; rs2301254 OR 1.65, P = 0.049; rs1799937 OR 1.91, P = 0.005] in the non-HIV-1 group and rs2234591 (OR 0.234, P = 0.011) in the HIV-1 group. Haplotype analyses in the population revealed that seven SNPs were associated with FSGS; five SNPs had the highest contingency score [-log10(P value) = 13.57] in the HIV-1 group. This association could not be explained by population substructure. We conclude that SNPs in WT1 and WIT1 genes are significantly associated with FSGS, suggesting that variants in these genes may mediate pathogenesis by altering WT1 function. Furthermore, HIV-1 infection status interacts with genetic variations in both genes to influence this phenotype. We speculate that nephropathy liability alleles in WT1 pathway genes cause podocyte dysfunction and glomerular scarring.
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Affiliation(s)
- Mohammed S Orloff
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio 44106-7281, USA
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19
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Iyengar SK, Fox KA, Schachere M, Manzoor F, Slaughter ME, Covic AM, Orloff SM, Hayden PS, Olson JM, Schelling JR, Sedor JR. Linkage analysis of candidate loci for end-stage renal disease due to diabetic nephropathy. J Am Soc Nephrol 2003; 14:S195-201. [PMID: 12819328 DOI: 10.1097/01.asn.0000070078.66465.55] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Diabetic nephropathy (DN), a major cause of ESRD, is undoubtedly multifactorial and is caused by environmental and genetic factors. To identify a genetic basis for DN susceptibility, we are collecting multiplex DN families in the Caucasian (CA) and African-American (AA) populations for whole genome scanning and candidate gene analysis. A candidate gene search of diabetic sibs discordantly affected, concordantly affected and concordantly unaffected for DN was performed with microsatellite markers in genomic regions suspected to harbor nephropathy susceptibility loci. Regions examined were at human chromosome 10p,10q (orthologous to the rat renal susceptibility Rf-1 locus), and at NPHS1 (nephrin), CD2AP, Wilms tumor (WT1), and NPHS2 (podocin) loci. Linkage analyses were conducted using model-free methods (SIBPAL, S.A.G.E.) for AA, CA, and the combined sample. Allele frequencies and the identity by descent sharing were estimated separately for AA and CA, and race was included as a covariate in the final linkage analysis. To date, we have collected 212 sib pairs from 46 CA and 50 AA families. The average age of diabetes onset was 46.8 yr versus 36.2 yr for CA and 39.5 yr versus 40.2 yr for AA, in males versus females respectively. Genotyping data were available for 106 sib pairs (43 CA, 63 AA) from 27 CA (44% male probands) and 38 AA families (43% male probands). Average AA and CA sibship size was 2.73. Singlepoint and multipoint linkage analyses indicate that marker D10S1654 on chromosome 10p is potentially linked to DN (CA only multipoint P = 4 x 10(-3)). Interestingly, the majority of the linkage evidence derives from the CA sib pairs. We are now adding sib pairs and increasing marker density on chromosome 10. We have excluded linkage with candidate regions for nephrin, CD2AP, WT1, and podocin in this sample. In conjunction with previous reports, our data support evidence for a DN susceptibility locus on chromosome 10.
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Affiliation(s)
- Sudha K Iyengar
- Department of Epidemiology, Case Western Reserve University, Cleveland, Ohio, USA.
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20
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Rana K, Isbel N, Buzza M, Dagher H, Henning P, Kainer G, Savige J. Clinical, histopathologic, and genetic studies in nine families with focal segmental glomerulosclerosis. Am J Kidney Dis 2003; 41:1170-8. [PMID: 12776268 DOI: 10.1016/s0272-6386(03)00347-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Familial forms of focal segmental glomerulosclerosis (FSGS) are caused by mutations in genes at 1q25-31 (gene for steroid-resistant nephrotic syndrome 2 [NPHS2]), 11q21-22, 19q13 (gene for alpha-actinin 4 and NPHS1), and at additional unidentified chromosomal loci. METHODS We describe clinical and histopathologic features and results of linkage analysis in nine consecutive index cases with familial FSGS who, together with their families, were referred for genetic studies. RESULTS Two of the index cases presented in childhood (22%) and seven cases presented in adolescence or adulthood (78%). Six of their families (67%), including the two cases with childhood-onset disease, showed probable autosomal recessive inheritance. FSGS segregated at the 1q25-31 locus in two of these families and at the 11q21-22 locus in four families. None had disease caused by mutations in genes at the 19q13 locus, and no locus was identified in the three remaining families. Clinical features of proteinuria, minimal hematuria, hypertension, preeclampsia, and progressive renal impairment were usually present with autosomal recessive or dominant inheritance and with disease that segregated at the different loci. Eighteen renal biopsies from affected members of eight families showed a strong correlation between tubulointerstitial damage and percentage of obsolescent glomeruli (rho = +0.76; P < 0.01). None of the 13 patients from eight families who underwent transplantation developed recurrent FSGS in their grafts. In general, carriers of autosomal recessive disease had no distinctive clinical features apart from the development of preeclampsia in successive pregnancies. CONCLUSION Familial forms of FSGS are not uncommon, and presentation frequently is in adolescence or adulthood, even when inheritance is autosomal recessive. Furthermore, carriers of autosomal recessive FSGS often have no distinctive phenotype.
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MESH Headings
- Adolescent
- Adult
- Age of Onset
- Aged
- Biopsy
- Child
- Chromosomes, Human, Pair 1/genetics
- Chromosomes, Human, Pair 11/genetics
- Female
- Genes, Dominant
- Genes, Recessive
- Genetic Heterogeneity
- Glomerulosclerosis, Focal Segmental/epidemiology
- Glomerulosclerosis, Focal Segmental/genetics
- Glomerulosclerosis, Focal Segmental/pathology
- Hematuria/etiology
- Humans
- Hypertension, Renal/etiology
- Kidney/pathology
- Lod Score
- Male
- Middle Aged
- Pedigree
- Pre-Eclampsia/etiology
- Pregnancy
- Proteinuria/etiology
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Affiliation(s)
- Kesha Rana
- University Department of Medicine, Austin and Repatriation Medical Centre, Heidelberg, VIC, Australia
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21
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Winn MP. Not all in the family: mutations of podocin in sporadic steroid-resistant nephrotic syndrome. J Am Soc Nephrol 2002; 13:577-579. [PMID: 11805190 DOI: 10.1681/asn.v132577] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Michelle P Winn
- Division of Nephrology, Duke University Medical Center, Durham, North Carolina
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22
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Abstract
Focal segmental glomerulosclerosis (FSGS) is the histologic expression of diverse processes affecting the renal glomeruli and occurring in primary and secondary forms. A number of pathogenic factors have been identified in primary FSGS, and multiple etiologies have been defined as contributing factors for the development of secondary FSGS. There is a complex interplay between etiologic and pathogenic factors, progression factors and intervention in the phenotypic expression of FSGS. Key components include genetic predisposition, environmental influences and the impact on phenotype of pharmacologic intervention. The phenotypic spectrum for FSGS ranges from mild proteinuria and slow progression to a devastating clinical syndrome characterized by heavy proteinuria and rapid loss of renal function over a period of months. While the pathogenesis is unknown, much is known about factors which are involved in the development and progression of both primary and secondary FSGS. The ultimate goal of understanding pathogenesis is to provide specific nontoxic therapy for those patients who have a definable form of FSGS. While this goal is not yet in sight, many types of intervention, not addressed in the current chapter, can influence the course of various diseases presenting as FSGS. Until specific therapy can be fashioned, it is necessary for the clinician caring for these patients to appreciate the complex interaction of pathogenetic factors involved in the development and pregression of FSGS, as a rationale for providing intervention to prevent development of the disease and to slow its course.
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Affiliation(s)
- W K Bolton
- Division of Nephrology, University of Virginia Health System, Charlottesville, VA 22908, USA.
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23
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Gilbert F. Disease genes and chromosomes: disease maps of the human genome. GENETIC TESTING 2001; 4:409-26. [PMID: 11216668 DOI: 10.1089/109065700750065180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- F Gilbert
- Weill Medical College of Cornell University, New York, NY 10021, USA.
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24
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Branten AJ, van den Born J, Jansen JL, Assmann KJ, Wetzels JF. Familial nephropathy differing from minimal change nephropathy and focal glomerulosclerosis. Kidney Int 2001; 59:693-701. [PMID: 11168951 DOI: 10.1046/j.1523-1755.2001.059002693.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Nephrotic syndrome in childhood is mainly due to minimal change nephropathy. In general, it is characterized by selective proteinuria, by steroid responsiveness, and histologically by podocytic foot process effacement. Familial presentation is rare and mainly restricted to one generation. METHODS We describe the occurrence of a familial nephropathy in a mother and two daughters. An initial diagnosis of minimal change nephropathy was made, but subsequently unique features became apparent. During follow-up, detailed studies of renal function and urinary protein excretion were performed. Available frozen renal biopsy material was revised and processed for immunofluorescence to detect abnormalities in the expression of heparan sulfate proteoglycans. The latter results were compared with renal biopsies of a control group composed of five adult patients with minimal change nephropathy. RESULTS The mother and two daughters were proteinuric since their early childhood. The mother revealed a persistent nephrotic syndrome for more than 20 years despite treatment with various immunosuppressive drugs. Likewise, treatment with prednisone was ineffective in the daughters. All three patients retained normal renal function during follow-up. Detailed measurements revealed that the proteinuria was incredibly selective (selectivity index approximately 0.01), and there was no evidence of tubulointerstitial damage, as reflected by a normal excretion of the low-molecular weight proteins beta(2)-microglobulin and alpha1-microglobulin. Renal biopsy performed in the mother and one daughter was thought to be compatible with minimal change nephropathy. However, histologically, two remarkable findings were made. By electron microscopy, there was no evidence of foot process retraction; specifically, the foot process width and slit pore diameter were normal. Furthermore, in contrast to the control patients, the expression of heparan sulfate polysaccharide side chains, as reflected by the staining with monoclonal antibody JM403, was normal. CONCLUSIONS We propose that this family represents a new familial nephropathy. The molecular basis of the permeability defect remains to be identified.
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Affiliation(s)
- A J Branten
- Division of Nephrology, Department of Medicine, University Hospital Nijmegen, Nijmegen, The Netherlands.
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25
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Fuchshuber A, Mehls O. Familial steroid-resistant nephrotic syndromes: recent advances. Nephrol Dial Transplant 2000; 15:1897-900. [PMID: 11096125 DOI: 10.1093/ndt/15.12.1897] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Tsukaguchi H, Yager H, Dawborn J, Jost L, Cohlmia J, Abreu PF, Pereira AB, Pollak MR. A locus for adolescent and adult onset familial focal segmental glomerulosclerosis on chromosome 1q25-31. J Am Soc Nephrol 2000; 11:1674-1680. [PMID: 10966492 DOI: 10.1681/asn.v1191674] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Focal segmental glomerulosclerosis is a nonspecific renal lesion observed both as a primary (idiopathic) entity and in a secondary form, typically in association with reduced functional renal mass. Familial forms have been observed and two loci for autosomal dominant FSGS have been mapped. This study shows that an adolescent/adult form of recessive FSGS maps to a locus on chromosome 1q25-31, which overlaps with a region previously identified as harboring a locus for an early childhood onset recessive form of nephrotic syndrome (SRN1). Evaluation of a large family demonstrated linkage with a maximum two-point lod score of 3.98 at D1S254 and D1S222. Lod score calculations support the conclusion of linkage in four of five additional families. Haplotype analysis suggests that this FSGS gene is located in a 19-cM region flanked by D1S416 and D1S413, of which 6 cM overlaps with SRN1, suggesting that these distinct clinical subsets of kidney disease may be allelic. These regions may also overlap with the syntenic region of the glomerulosclerosis susceptibility locus in the BUF/Mna rat. Because the presentation of FSGS may be subtle, inherited FSGS may be much more common than generally realized and grossly underestimated because of the absence of clear familial patterns. This result increases the suspicion that polymorphisms at this locus may contribute to sporadic FSGS.
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Affiliation(s)
- Hiroyasu Tsukaguchi
- Renal Division and Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
| | - Henry Yager
- Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts
| | - John Dawborn
- Department of Nephrology, Austin and Repatriation Medical Centre, Heidelberg, Australia
| | - Luis Jost
- Division of Nephrology, Instituto Universitario CEMIC, Buenos Aires, Argentina
| | - Jerry Cohlmia
- University of Kansas School of Medicine, Wichita, Kansas
| | - Patricia F Abreu
- Division of Nephrology, Department of Medicine, Universidade Federal de São Paulo, Brazil
| | - Aparecido B Pereira
- Division of Nephrology, Department of Medicine, Universidade Federal de São Paulo, Brazil
| | - Martin R Pollak
- Renal Division and Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
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27
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Hsu SI, Ramirez SB, Winn MP, Bonventre JV, Owen WF. Evidence for genetic factors in the development and progression of IgA nephropathy. Kidney Int 2000; 57:1818-35. [PMID: 10792601 DOI: 10.1046/j.1523-1755.2000.00032.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND IgA nephropathy (IgAN) is the most common glomerulonephritis in the world among patients undergoing renal biopsy. Once considered a relatively benign condition, longitudinal follow-up studies have revealed that in fact 9 to 50% of patients progress to end-stage renal disease within 20 years of disease onset. In the three decades since its first description by Jean Berger and Nicole Hinglais, clinical, epidemiologic, and immunologic studies of the pathogenesis of primary (idiopathic) mesangial glomerulonephritis with predominant IgA deposits have characterized the features of IgAN as a distinct glomerular disease entity. However, the basic molecular mechanism(s) underlying abnormal IgA deposition in the mesangium with ensuing extracellular matrix expansion and mesangial cell proliferation remains poorly understood. The task of elucidating the molecular basis of IgAN is made especially challenging by the fact that both environmental and genetic components likely contribute to the development and progression of IgAN. METHODS AND RESULTS We review here the evidence for genetic factors in the development and progression of IgAN, including a reappraisal of earlier conflicting results from small immunogenetic case-control studies, the evidence for racial differences in the prevalence of IgAN, a detailed summary of all reported occurrences of familial IgAN worldwide, and an exhaustive review of new insights gained through the study of two murine models of hereditary IgAN: the ddY and the uteroglobin-deficient mouse. CONCLUSIONS With the development of powerful molecular genetic approaches to the study of both Mendelian and complex human genetic diseases, and the successful efforts of investigators to identify and clinically characterize large IgAN multiplex families, we propose that genetic analysis of familial IgAN is the most promising approach to the identification of IgAN disease/susceptibility genes. Alternatively, if the case-control study design is employed to identify associations between particular candidate genes or markers and the development of IgAN, spurious associations caused by the effects of population stratification should be ruled out by confirming the findings using powerful and sensitive family-based methodologies such as the transmission/dysequilibrium test (TDT).
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Affiliation(s)
- S I Hsu
- Departments of Medicine and Pediatrics, Faculty of Medicine, National University of Singapore.
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28
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Abstract
The role of cell cycle regulatory proteins in progression is elucidated. Human renal biopsy data show amelioration and even regression of structural injury with interventions. Data implicate new mechanisms of the renin-aldosterone-angiotensin system in progressive injuries, including immune modulation and a direct effect of aldosterone on progression. New approaches and interventions that target these fibrotic responses show promising results.
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Affiliation(s)
- A B Fogo
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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29
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Abstract
There are a large number of glomerular diseases that may be responsible for a nephrotic syndrome, the most frequent in childhood being minimal change disease. In the past few years, the molecular genetic basis of several conditions that may cause a nephrotic syndrome have been identified. Denys-Drash syndrome and Frasier syndrome are related diseases caused by mutations in the WT1 gene. Familial forms of idiopathic nephrotic syndrome with focal and segmental glomerular sclerosis/hyalinosis have been identified with an autosomal dominant or recessive mode of inheritance and linkage analysis have allowed to localize several genes on chromosomes 1, 11 and 17. The gene responsible for the Finnish type congenital nephrotic syndrome has been identified. This gene, named NPHS1, codes for nephrin, which is located at the slit diaphragm of the glomerular podocytes and is thought to play an essential role in the normal glomerular filtration barrier.
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Affiliation(s)
- R Salomon
- Pediatric Nephrology and INSERM U 423, Hôpital Necker-Enfants Malades, Paris, France
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30
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Vats A, Nayak A, Ellis D, Randhawa PS, Finegold DN, Levinson KL, Ferrell RE. Familial nephrotic syndrome: clinical spectrum and linkage to chromosome 19q13. Kidney Int 2000; 57:875-81. [PMID: 10720940 DOI: 10.1046/j.1523-1755.2000.057003875.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Familial nephrotic syndrome (NS) has both autosomal dominant and recessive forms of inheritance. Recent studies in families with an autosomal dominant form of focal segmental glomerulosclerosis (FSGS) have been at odds concerning linkage to chromosome 19q13 (Mathis et al, Kidney Int 53:282-286, 1998; Winn et al, Kidney Int 55:1241-1246, 1999), suggesting genetic heterogeneity. This study examines the clinical features and confirms linkage to chromosome 19q13 in a family with autosomal dominant NS. METHODS DNA samples were obtained from 16 of 17 family members. Genomic DNA was isolated, and polymerase chain reaction was performed for five markers spanning the area of interest on chromosome 19q13. Data were evaluated using two- and six-point linkage analysis. RESULTS Clinical features included presentation of NS in childhood, steroid unresponsiveness, and slow progression to renal failure. Renal biopsy in affected family members showed lesions ranging from minimal change to mesangial proliferative glomerulonephritis to FSGS. Linkage was confirmed between the disease state and chromosome 19q13, with a maximum logarithm of odds (LOD) score of 2.41. Linkage was observed for a 7 cM region on chromosome 19q13, defined by markers D19S425 and D19S220. CONCLUSIONS This study confirms the Mathis et al report of linkage to chromosome 19q13 in a family with autosomal dominant NS. However, there were notable differences in the presenting clinical and histopathologic features of our affected family members compared with those of Mathis et al. This suggests that the gene on chromosome 19q13 may be responsible for considerable phenotypic heterogeneity and variable expression in both clinical presentation and renal histopathology.
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Affiliation(s)
- A Vats
- Department of Pediatrics, Children's Hospital of Pittsburgh, Pennsylvania, USA.
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