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Sharova M, Markova T, Sumina M, Petukhova M, Bulakh M, Ryzhkova O, Nagornova T, Ionova S, Marakhonov A, Dadali E, Kutsev S. Rare IFT140-Associated Phenotype of Cranioectodermal Dysplasia and Features of Diagnostic Journey in Patients with Suspected Ciliopathies. Genes (Basel) 2023; 14:1553. [PMID: 37628605 PMCID: PMC10454909 DOI: 10.3390/genes14081553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Here we present a patient with a cranioectodermal phenotype associated with pathogenic variants in the IFT140 gene. Most frequently, pathogenic variants in IFT140 correspond to the phenotype of Mainzer-Saldino syndrome. Only four patients have previously been described with this cranioectodermal phenotype and variants in IFT140. In comparison to other IFT140-cranioectodermal patients, our proband had similar skeletal features among with early onset end-stage renal failure that required kidney transplantation but did not have common ophthalmological features such as retinopathy, optic nerve atrophy, or nystagmus. Following exome sequencing, a splicing variant and exons 27-30 tandem duplication were suspected and further validated. The two other patients with Mainzer-Saldino syndrome that we described displayed a typical clinical picture but a special diagnostic journey. In both cases, at first only one pathogenic variant was detected following panel or exome NGS sequencing. Further WGS was performed for one of them where tandem duplication was found. Screening the third patient for the same tandem duplication was successful and revealed the presence of this duplication. Thus, we suggest that the description of the clinical feature polymorphism in a rare IFT140-cranioectodermal phenotype is extremely important for providing genetic counseling for families, as well as the formation of the correct diagnostic path for patients with a variant in IFT140.
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Affiliation(s)
| | | | - Maria Sumina
- State Healthcare Institution of Sverdlovsk Region “Clinical and Diagnostic Center “Mother’s and Child Health Protection”, 620067 Ekaterinburg, Russia
| | | | - Maria Bulakh
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | - Oxana Ryzhkova
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | | | - Sofya Ionova
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | | | - Elena Dadali
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | - Sergey Kutsev
- Research Centre for Medical Genetics, 115522 Moscow, Russia
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Zhou Q, Weng Q, Zhang X, Liu Y, Tong J, Hao X, Shi H, Shen P, Ren H, Xie J, Chen N. Association Between NPHS2 p.R229Q and Focal Segmental Glomerular Sclerosis/Steroid-Resistant Nephrotic Syndrome. Front Med (Lausanne) 2022; 9:937122. [PMID: 35935761 PMCID: PMC9354893 DOI: 10.3389/fmed.2022.937122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/01/2022] [Indexed: 01/10/2023] Open
Abstract
Aim NPHS2 is the coding gene of podocin. This study aims to investigate the association between NPHS2 p.R229Q (rs61747728), the most frequently reported missense variant of NPHS2, and focal segmental glomerular sclerosis (FSGS) or steroid-resistant nephrotic syndrome (SRNS) based on typing the variant in a Chinese FSGS/SRNS cohort and conducting a meta-analysis. Method We recruited patients with FSGS or SRNS and healthy individuals. To conduct a meta-analysis, all studies on p.R229Q and FSGS/SRNS were searched from public databases. Results In total, we enrolled 204 patients with FSGS, 61 patients with SRNS [46 with FSGS, 9 with minimal change disease (MCD), and six patients with IgA nephropathy (IgAN)], and 100 healthy controls. Unexpectedly, p.R229Q was absent in the patients from our cohort. By meta-analysis of 21 studies including 2,489 patients with FSGS/SRNS and 6,004 healthy controls, we confirmed that the A allele of p.R229Q was significantly associated with increased risk of FSGS/SRNS (allelic OR = 1.9, 95% CI = 1.44-2.52, P < 0.001). However, the subgroup analysis showed that the association between p.R229Q and FSGS/SRNS was true only in Caucasians (allelic OR = 2.14, 95%CI = 1.54-2.98, P < 0.001) and in early-onset patients (allelic OR: 2.13, 95% CI = 1.21-3.76, P = 0.009). Conclusion NPHS2 p.R229Q may play an important role in enhancing the susceptibility of FSGS/SRNS, especially in ethnicity of Caucasian and age of early-onset patients.
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Affiliation(s)
- Qiongxiu Zhou
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Department of Nephrology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Qinjie Weng
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoyan Zhang
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yunzi Liu
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jun Tong
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xu Hao
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Hao Shi
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Pingyan Shen
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Hong Ren
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jingyuan Xie
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Jingyuan Xie,
| | - Nan Chen
- Department of Nephrology, Institute of Nephrology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Nan Chen,
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Gu Y, Han B, Zhu X, Chen Y. Prenatal diagnosis of congenital nephrotic syndrome of the Finnish type in a Chinese family. Taiwan J Obstet Gynecol 2021; 60:758-762. [PMID: 34247820 DOI: 10.1016/j.tjog.2021.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2021] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE To explore the genetic bias in a Chinese family suspected of having congenital nephrotic syndrome of the Finnish type (CNF). CASE REPORT We developed a prenatal genetic diagnosis in a Chinese family with CNF. A single heterozygous mutation (c.3213delG) was found in the foetus IId and we presumed that it was an asymptomatic carrier of the normal phenotype. Additionally, two compound heterozygous variants (c.3213delG and c.3478C > T) were discovered in the foetus IIe, which were inherited from the mother and father, respectively. We performed further pathological examinations after medical abortion. Kidney histopathology and immunofluorescence results were similar to those reported in previous studies. CONCLUSION Prenatal genetic diagnosis of CNF still requires further research to explore the pathogenicity of suspected mutations.
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Affiliation(s)
- Yuling Gu
- First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Bing Han
- First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China.
| | - Xiaolan Zhu
- First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Youguo Chen
- First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
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Joshi A, Sinha A, Sharma A, Shamim U, Uppilli B, Sharma P, Zahra S, Parveen S, Mathur A, Chandan M, Tewari P, Khandelwal P, Hari P, Mukerji M, Faruq M, Bagga A. Next-Generation Sequencing for Congenital Nephrotic Syndrome: A Multi-Center Cross-Sectional Study from India. Indian Pediatr 2021. [DOI: 10.1007/s13312-021-2215-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Genetic studies of focal segmental glomerulosclerosis: a waste of scientific time? Pediatr Nephrol 2020; 35:9-16. [PMID: 30591974 PMCID: PMC6901409 DOI: 10.1007/s00467-018-4161-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/27/2018] [Accepted: 11/28/2018] [Indexed: 12/21/2022]
Abstract
Many genetic causes of focal segmental glomerulosclerosis (FSGS) have been described. A paradox is that the science in the molecular biology, which generally appears of high quality, is not mirrored by a similarly critical analysis of the renal pathology. FSGS has been applied to such a wide range of conditions that it can reasonably be said to have no useful meaning. Attempts to refine the term have been largely ignored. Study of 252 papers on genetic causes of FSGS found various clinical features. Many papers took the reported diagnosis without question. Few papers reported a pathological review, almost half reported FSGS and up to six other conditions caused by any particular gene, some reported FSGS with recognisable glomerular disorders, over 80% did not apply the Columbia classification, and in nearly all with photomicrographs, the images were not useful for refinement of FSGS. Some workers commented on a lack of genotype-phenotype correlation. One reason is a disregard of the principle that scientific investigation requires an unambiguous definition of the condition studied, to allow others to replicate or refute the findings. Genetic studies of FSGS should use a similarly rigorous approach to renal pathology to that used in molecular biology.
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Schapiro D, Daga A, Lawson JA, Majmundar AJ, Lovric S, Tan W, Warejko JK, Fessi I, Rao J, Airik M, Gee HY, Schneider R, Widmeier E, Hermle T, Ashraf S, Jobst-Schwan T, van der Ven AT, Nakayama M, Shril S, Braun DA, Hildebrandt F. Panel sequencing distinguishes monogenic forms of nephritis from nephrosis in children. Nephrol Dial Transplant 2019; 34:474-485. [PMID: 30295827 DOI: 10.1093/ndt/gfy050] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/21/2018] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Alport syndrome (AS) and atypical hemolytic-uremic syndrome (aHUS) are rare forms of chronic kidney disease (CKD) that can lead to a severe decline of renal function. Steroid-resistant nephrotic syndrome (SRNS) is more common than AS and aHUS and causes 10% of childhood-onset CKD. In recent years, multiple monogenic causes of AS, aHUS and SRNS have been identified, but their relative prevalence has yet to be studied together in a typical pediatric cohort of children with proteinuria and hematuria. We hypothesized that identification of causative mutations by whole exome sequencing (WES) in known monogenic nephritis and nephrosis genes would allow distinguishing nephritis from nephrosis in a typical pediatric group of patients with both proteinuria and hematuria at any level. METHODS We therefore conducted an exon sequencing (WES) analysis for 11 AS, aHUS and thrombotic thrombocytopenic purpura-causing genes in an international cohort of 371 patients from 362 families presenting with both proteinuria and hematuria before age 25 years. In parallel, we conducted either WES or high-throughput exon sequencing for 23 SRNS-causing genes in all patients. RESULTS We detected pathogenic mutations in 18 of the 34 genes analyzed, leading to a molecular diagnosis in 14.1% of families (51 of 362). Disease-causing mutations were detected in 3 AS-causing genes (4.7%), 3 aHUS-causing genes (1.4%) and 12 NS-causing genes (8.0%). We observed a much higher mutation detection rate for monogenic forms of CKD in consanguineous families (35.7% versus 10.1%). CONCLUSIONS We present the first estimate of relative frequency of inherited AS, aHUS and NS in a typical pediatric cohort with proteinuria and hematuria. Important therapeutic and preventative measures may result from mutational analysis in individuals with proteinuria and hematuria.
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Affiliation(s)
- David Schapiro
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ankana Daga
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jennifer A Lawson
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amar J Majmundar
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Svjetlana Lovric
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Weizhen Tan
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jillian K Warejko
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Inés Fessi
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jia Rao
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Merlin Airik
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Heon Yung Gee
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ronen Schneider
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Eugen Widmeier
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tobias Hermle
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shazia Ashraf
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tilman Jobst-Schwan
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amelie T van der Ven
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Makiko Nakayama
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shirlee Shril
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniela A Braun
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Friedhelm Hildebrandt
- Department of Medicine, Division of Nephrology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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Wang F, Zhang Y, Mao J, Yu Z, Yi Z, Yu L, Sun J, Wei X, Ding F, Zhang H, Xiao H, Yao Y, Tan W, Lovric S, Ding J, Hildebrandt F. Spectrum of mutations in Chinese children with steroid-resistant nephrotic syndrome. Pediatr Nephrol 2017; 32:1181-1192. [PMID: 28204945 PMCID: PMC5478193 DOI: 10.1007/s00467-017-3590-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 12/06/2016] [Accepted: 12/23/2016] [Indexed: 01/21/2023]
Abstract
BACKGROUND The aim of this study was to elucidate whether genetic screening test results of pediatric patients with steroid-resistant nephrotic syndrome (SRNS) vary with ethnicity. METHODS Using high-throughput DNA sequencing, 28 nephrotic syndrome-related genes were analyzed in 110 chil-dren affected by SRNS and 10 children with isolated proteinuria enrolled by 5 centers in China (67 boys, 53 girls). Their age at disease onset ranged from 1 day to 208 months (median, 48.8 months). Patients were excluded if their age at onset of disease was over 18 years or if they were diagnosed as having Alport syndrome. RESULTS A genetic etiology was identified in 28.3% of our cohort and the likelihood of establishing a genetic diagnosis decreased as the age at onset of nephrotic syndrome increased. The most common mutated genes were ADCK4 (6.67%), NPHS1 (5.83%), WT1 (5.83%), and NPHS2 (3.33%), and the difference in the frequencies of ADCK4 and NPHS2 mutations between this study and a study on monogenic causes of SRNS in the largest international cohort of 1,783 different families was significant. A case of congenital nephrotic syndrome was attributed to a homozygous missense mutation in ADCK4, and a de novo missense mutation in TRPC6 was detected in a case of infantile nephrotic syndrome. CONCLUSIONS Our results showed that, in the first and the largest multicenter cohort of Chinese pediatric SRNS reported to date, ADCK4 is the most common causative gene, whereas there is a low prevalence of NPHS2 mutations. Our data indicated that the genetic testing results for pediatric SRNS patients vary with different ethnicities, and this information will help to improve management of the disease in clinical practice.
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Affiliation(s)
- Fang Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Yanqin Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Jianhua Mao
- Department of Nephrology, The Children Hospital of Zhejiang University School of Medicine, Hangzhou, P. R. China
| | - Zihua Yu
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fuzhou, P. R. China
| | - Zhuwen Yi
- Department of Pediatrics, The second Xiangya Hospital, Central South University, Changsha, P. R. China
| | - Li Yu
- Department of Pediatrics, Guangzhou First People’s Hospital, Guangzhou, P. R. China
| | - Jun Sun
- Binhai Genomics Institute, Tianjin Translational Genomics Center, BGI-Tianjin, BGI-shenzhen, Tianjin, P. R. China,BGI-Shenzhen, Shenzhen, P. R. China
| | - Xiuxiu Wei
- Binhai Genomics Institute, Tianjin Translational Genomics Center, BGI-Tianjin, BGI-shenzhen, Tianjin, P. R. China,BGI-Shenzhen, Shenzhen, P. R. China
| | - Fangrui Ding
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Hongwen Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Huijie Xiao
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Yong Yao
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Weizhen Tan
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Svjetlana Lovric
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, No. 1, Xi An Men Da Jie, Beijing, 100034, People's Republic of China.
| | - Friedhelm Hildebrandt
- Division of Nephrology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Enders 561, Boston, MA, 02115, USA.
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R229Q Polymorphism of NPHS2 Gene in Group of Iraqi Children with Steroid-Resistant Nephrotic Syndrome. Int J Nephrol 2017; 2017:1407506. [PMID: 28529802 PMCID: PMC5424166 DOI: 10.1155/2017/1407506] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 03/24/2017] [Accepted: 04/10/2017] [Indexed: 11/24/2022] Open
Abstract
Background. The polymorphism R229Q is one of the most commonly reported podocin sequence variations among steroid-resistant nephrotic syndromes (SRNS). Aim of the Study. We investigated the frequency and risk of this polymorphism among a group of Iraqi children with SRNS and steroid-sensitive nephrotic syndrome (SSNS). Patients and Methods. A prospective case control study which was conducted in Al-Imamein Al-Kadhimein Medical City, spanning the period from the 1st of April 2015 to 30th of November 2015. Study sample consisted of 54 children having NS, divided into 2 groups: patients group consisted of 27 children with SRNS, and control group involved 27 children with SSNS. Both were screened by real time polymerase chain reaction for R229Q in exon 5 of NPHS2 gene. Results. Molecular study showed R229Q polymorphism in 96.3% of SRNS and 100% of SSNS. There were no phenotypic or histologic characteristics of patients bearing homozygous R229Q polymorphism and the patients with heterozygous R229Q polymorphism. Conclusion. Polymorphism R229Q of NPHS2 gene is prevalent in Iraqi children with SRNS and SSNS. Further study needs to be done, for other exons and polymorphism of NPHS2 gene in those patients.
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Ha TS. Genetics of hereditary nephrotic syndrome: a clinical review. KOREAN JOURNAL OF PEDIATRICS 2017; 60:55-63. [PMID: 28392820 PMCID: PMC5383633 DOI: 10.3345/kjp.2017.60.3.55] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 05/18/2016] [Accepted: 05/25/2016] [Indexed: 01/01/2023]
Abstract
Advances in podocytology and genetic techniques have expanded our understanding of the pathogenesis of hereditary steroid-resistant nephrotic syndrome (SRNS). In the past 20 years, over 45 genetic mutations have been identified in patients with hereditary SRNS. Genetic mutations on structural and functional molecules in podocytes can lead to serious injury in the podocytes themselves and in adjacent structures, causing sclerotic lesions such as focal segmental glomerulosclerosis or diffuse mesangial sclerosis. This paper provides an update on the current knowledge of podocyte genes involved in the development of hereditary nephrotic syndrome and, thereby, reviews genotype-phenotype correlations to propose an approach for appropriate mutational screening based on clinical aspects.
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Affiliation(s)
- Tae-Sun Ha
- Department of Pediatrics, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Korea
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Crawford BD, Gillies CE, Robertson CC, Kretzler M, Otto EA, Vega-Warner V, Sampson MG. Evaluating Mendelian nephrotic syndrome genes for evidence for risk alleles or oligogenicity that explain heritability. Pediatr Nephrol 2017; 32:467-476. [PMID: 27766458 PMCID: PMC5483602 DOI: 10.1007/s00467-016-3513-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/25/2016] [Accepted: 08/29/2016] [Indexed: 01/08/2023]
Abstract
BACKGROUND More than 30 genes can harbor rare exonic variants sufficient to cause nephrotic syndrome (NS), and the number of genes implicated in monogenic NS continues to grow. However, outside the first year of life, the majority of affected patients, particularly in ancestrally mixed populations, do not have a known monogenic form of NS. Even in those children classified with a monogenic form of NS, there is phenotypic heterogeneity. Thus, we have only discovered a fraction of the heritability of NS-the underlying genetic factors contributing to phenotypic variation. Part of the "missing heritability" for NS has been posited to be explained by patients harboring coding variants across one or more previously implicated NS genes, insufficient to cause NS in a classical Mendelian manner, but that nonetheless have a sufficient impact on protein function to cause disease. However, systematic evaluation in patients with NS for rare or low-frequency risk alleles within single genes, or in combination across genes ("oligogenicity"), has not been reported. To determine whether, compared with a reference population, patients with NS have either a significantly increased burden of protein-altering variants ("risk-alleles"), or a unique combination of them ("oligogenicity"), in a set of 21 genes implicated in Mendelian forms of NS. METHODS In 303 patients with NS enrolled in the Nephrotic Syndrome Study Network (NEPTUNE), we performed targeted amplification paired with next-generation sequencing of 21 genes implicated in monogenic NS. We created a high-quality variant call set and compared it with a variant call set of the same genes in a reference population composed of 2,535 individuals from phase 3 of the 1000 Genomes Project. We created both a "stringent" and a "relaxed" pathogenicity-filtering pipeline, applied them to both cohorts, and computed the burden of variants in the entire gene set per cohort, the burden of variants in the entire gene set per individual, the burden of variants within a single gene per cohort, and unique combinations of variants across two or more genes per cohort. RESULTS With few exceptions when using the relaxed filter, and which are likely the result of confounding by population stratification, NS patients did not have a significantly increased burden of variants in Mendelian NS genes in comparison to a reference cohort, nor was there any evidence for oligogenicity. This was true when using both the relaxed and the stringent variant pathogenicity filter. CONCLUSION In our study, there were no significant differences in the burden or particular combinations of low-frequency or rare protein-altering variants in a previously implicated Mendelian NS genes cohort between North American patients with NS and a reference population. Studies in larger independent cohorts or meta-analyses are needed to assess the generalizability of our discoveries and also address whether there is in fact small but significant enrichment of risk alleles or oligogenicity in NS cases that was undetectable with this current sample size. It is still possible that rare protein-altering variants in these genes, insufficient to cause Mendelian disease, still contribute to NS as risk alleles and/or via oligogenicity. However, we suggest that more accurate bioinformatic analyses and the incorporation of functional assays would be necessary to identify bona fide instances of this form of genetic architecture as a contributor to the heritability of NS.
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Affiliation(s)
- Brendan D Crawford
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA
| | - Christopher E Gillies
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA
| | - Catherine C Robertson
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA
| | - Matthias Kretzler
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Edgar A Otto
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Virginia Vega-Warner
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA
| | - Matthew G Sampson
- Department of Pediatrics, University of Michigan Medical School, 3560B MSRB 2, Ann Arbor, MI, USA.
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11
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Weber S, Büscher AK, Hagmann H, Liebau MC, Heberle C, Ludwig M, Rath S, Alberer M, Beissert A, Zenker M, Hoyer PF, Konrad M, Klein HG, Hoefele J. Dealing with the incidental finding of secondary variants by the example of SRNS patients undergoing targeted next-generation sequencing. Pediatr Nephrol 2016; 31:73-81. [PMID: 26248470 DOI: 10.1007/s00467-015-3167-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 06/29/2015] [Accepted: 06/30/2015] [Indexed: 01/15/2023]
Abstract
BACKGROUND Steroid-resistant nephrotic syndrome (SRNS) is a severe cause of progressive renal disease. Genetic forms of SRNS can present with autosomal recessive or autosomal dominant inheritance. Recent studies have identified mutations in multiple podocyte genes responsible for SRNS. Improved sequencing methods (next-generation sequencing, NGS) now promise rapid mutational testing of SRNS genes. METHODS In the present study, a simultaneous screening of ten SRNS genes in 37 SRNS patients was performed by NGS. RESULTS In 38 % of the patients, causative mutations in one SRNS gene were found. In 22 % of the patients, in addition to these mutations, a secondary variant in a different gene was identified. CONCLUSIONS This high incidence of accumulating sequence variants was unexpected but, although they might have modifier effects, the pathogenic potential of these additional sequence variants seems unclear so far. The example of molecular diagnostics by NGS in SRNS patients shows that these new sequencing technologies might provide further insight into molecular pathogenicity in genetic disorders but will also generate results, which will be difficult to interpret and complicate genetic counseling. Although NGS promises more frequent identification of disease-causing mutations, the identification of causative mutations, the interpretation of incidental findings and possible pitfalls might pose problems, which hopefully will decrease by further experience and elucidation of molecular interactions.
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Affiliation(s)
- Stefanie Weber
- Pediatric Nephrology, Pediatrics II, University of Duisburg-Essen, Essen, Germany
| | - Anja K Büscher
- Pediatric Nephrology, Pediatrics II, University of Duisburg-Essen, Essen, Germany
| | - Henning Hagmann
- Renal Division, Department II of Internal Medicine and Center for Molecular Medicine, University of Cologne, Cologne, Germany
| | - Max C Liebau
- Renal Division, Department II of Internal Medicine and Center for Molecular Medicine, University of Cologne, Cologne, Germany
- Department of Pediatrics, University Hospital of Cologne, Cologne, Germany
| | - Christian Heberle
- Center for Human Genetics and Laboratory Diagnostics Dr. Klein, Dr. Rost and Colleagues, Martinsried, Germany
| | - Michael Ludwig
- Department of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | - Sabine Rath
- Center for Human Genetics and Laboratory Diagnostics Dr. Klein, Dr. Rost and Colleagues, Martinsried, Germany
| | - Martin Alberer
- Department of Infectious Diseases and Tropical Medicine, Ludwig-Maximilians University, Munich, Germany
| | - Antje Beissert
- Pediatric Nephrology, University Children's Hospital, Würzburg, Germany
| | - Martin Zenker
- Institute of Human Genetics, University Hospital, Magdeburg, Germany
| | - Peter F Hoyer
- Pediatric Nephrology, Pediatrics II, University of Duisburg-Essen, Essen, Germany
| | | | - Hanns-Georg Klein
- Center for Human Genetics and Laboratory Diagnostics Dr. Klein, Dr. Rost and Colleagues, Martinsried, Germany
| | - Julia Hoefele
- Center for Human Genetics and Laboratory Diagnostics Dr. Klein, Dr. Rost and Colleagues, Martinsried, Germany.
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12
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Sadowski CE, Lovric S, Ashraf S, Pabst WL, Gee HY, Kohl S, Engelmann S, Vega-Warner V, Fang H, Halbritter J, Somers MJ, Tan W, Shril S, Fessi I, Lifton RP, Bockenhauer D, El-Desoky S, Kari JA, Zenker M, Kemper MJ, Mueller D, Fathy HM, Soliman NA, Hildebrandt F. A single-gene cause in 29.5% of cases of steroid-resistant nephrotic syndrome. J Am Soc Nephrol 2015; 26:1279-89. [PMID: 25349199 PMCID: PMC4446877 DOI: 10.1681/asn.2014050489] [Citation(s) in RCA: 437] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 09/10/2014] [Indexed: 01/15/2023] Open
Abstract
Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of ESRD in the first two decades of life. Effective treatment is lacking. First insights into disease mechanisms came from identification of single-gene causes of SRNS. However, the frequency of single-gene causation and its age distribution in large cohorts are unknown. We performed exon sequencing of NPHS2 and WT1 for 1783 unrelated, international families with SRNS. We then examined all patients by microfluidic multiplex PCR and next-generation sequencing for all 27 genes known to cause SRNS if mutated. We detected a single-gene cause in 29.5% (526 of 1783) of families with SRNS that manifested before 25 years of age. The fraction of families in whom a single-gene cause was identified inversely correlated with age of onset. Within clinically relevant age groups, the fraction of families with detection of the single-gene cause was as follows: onset in the first 3 months of life (69.4%), between 4 and 12 months old (49.7%), between 1 and 6 years old (25.3%), between 7 and 12 years old (17.8%), and between 13 and 18 years old (10.8%). For PLCE1, specific mutations correlated with age of onset. Notably, 1% of individuals carried mutations in genes that function within the coenzyme Q10 biosynthesis pathway, suggesting that SRNS may be treatable in these individuals. Our study results should facilitate molecular genetic diagnostics of SRNS, etiologic classification for therapeutic studies, generation of genotype-phenotype correlations, and the identification of individuals in whom a targeted treatment for SRNS may be available.
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Affiliation(s)
- Carolin E Sadowski
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Svjetlana Lovric
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Shazia Ashraf
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Werner L Pabst
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Heon Yung Gee
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Stefan Kohl
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Susanne Engelmann
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Virginia Vega-Warner
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan
| | - Humphrey Fang
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jan Halbritter
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Michael J Somers
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Weizhen Tan
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Shirlee Shril
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Inès Fessi
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Richard P Lifton
- Department of Genetics and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut
| | - Detlef Bockenhauer
- Institute of Child Health, University College London, London, United Kingdom
| | - Sherif El-Desoky
- Pediatric Nephrology Unit, King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia
| | - Jameela A Kari
- Pediatric Nephrology Unit, King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia
| | - Martin Zenker
- Department of Human Genetics, Otto von Guericke University, Magdeburg, Germany
| | - Markus J Kemper
- Department of Pediatrics, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Dominik Mueller
- Department of Pediatric Nephrology, Medical Faculty of the Charité, Berlin, Germany
| | - Hanan M Fathy
- The Pediatric Nephrology Unit, Alexandria University, Alexandria, Egypt
| | - Neveen A Soliman
- Department of Pediatrics, Center of Pediatric Nephrology & Transplantation, Kasr Al Ainy School of Medicine, Cairo University, Cairo, Egypt; Egyptian Group for Orphan Renal Diseases, Cairo, Egypt; and
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; Howard Hughes Medical Institute, Chevy Chase, Maryland
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13
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Ng KH, Heng CK, Khor CC, Yap HK. Genes in FSGS: Diagnostic and Management Strategies in Children. CURRENT PEDIATRICS REPORTS 2015. [DOI: 10.1007/s40124-014-0064-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Mutation-dependent recessive inheritance of NPHS2-associated steroid-resistant nephrotic syndrome. Nat Genet 2014; 46:299-304. [PMID: 24509478 DOI: 10.1038/ng.2898] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 01/17/2014] [Indexed: 02/07/2023]
Abstract
Monogenic disorders result from defects in a single gene. According to Mendel's laws, these disorders are inherited in either a recessive or dominant fashion. Autosomal-recessive disorders require a disease-causing variant on both alleles, and according to our current understanding, their pathogenicities are not influenced by each other. Here we present an autosomal-recessive disorder, nephrotic syndrome type 2 (MIM 600995), in which the pathogenicity of an NPHS2 allele encoding p.Arg229Gln depends on the trans-associated mutation. We show that, contrary to expectations, this allele leads to a disease phenotype only when it is associated specifically with certain 3' NPHS2 mutations because of an altered heterodimerization and mislocalization of the encoded p.Arg229Gln podocin. The disease-associated 3' mutations exert a dominant-negative effect on p.Arg229Gln podocin but behave as recessive alleles when associated with wild-type podocin. Therefore, the transmission rates for couples carrying the disease-associated mutations and p.Arg229Gln may be substantially different from those expected in autosomal-recessive disorders.
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15
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Bouchireb K, Boyer O, Gribouval O, Nevo F, Huynh-Cong E, Morinière V, Campait R, Ars E, Brackman D, Dantal J, Eckart P, Gigante M, Lipska BS, Liutkus A, Megarbane A, Mohsin N, Ozaltin F, Saleem MA, Schaefer F, Soulami K, Torra R, Garcelon N, Mollet G, Dahan K, Antignac C. NPHS2Mutations in Steroid-Resistant Nephrotic Syndrome: A Mutation Update and the Associated Phenotypic Spectrum. Hum Mutat 2013; 35:178-86. [DOI: 10.1002/humu.22485] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 11/05/2013] [Indexed: 01/10/2023]
Affiliation(s)
- Karim Bouchireb
- Assistance Publique-Hôpitaux de Paris, Service de Néphrologie Pédiatrique; Centre de Référence des Maladies Rénales Héréditaires (MARHEA), Hôpital Necker-Enfants Malades; Paris France
- Inserm U983; Institut Imagine, Hôpital Necker-Enfants Malades; Paris France
- Université Paris Descartes-Sorbonne Paris Cité; Paris France
| | - Olivia Boyer
- Assistance Publique-Hôpitaux de Paris, Service de Néphrologie Pédiatrique; Centre de Référence des Maladies Rénales Héréditaires (MARHEA), Hôpital Necker-Enfants Malades; Paris France
- Inserm U983; Institut Imagine, Hôpital Necker-Enfants Malades; Paris France
- Université Paris Descartes-Sorbonne Paris Cité; Paris France
| | - Olivier Gribouval
- Inserm U983; Institut Imagine, Hôpital Necker-Enfants Malades; Paris France
- Université Paris Descartes-Sorbonne Paris Cité; Paris France
| | - Fabien Nevo
- Inserm U983; Institut Imagine, Hôpital Necker-Enfants Malades; Paris France
- Université Paris Descartes-Sorbonne Paris Cité; Paris France
| | - Evelyne Huynh-Cong
- Inserm U983; Institut Imagine, Hôpital Necker-Enfants Malades; Paris France
- Université Paris Descartes-Sorbonne Paris Cité; Paris France
| | - Vincent Morinière
- Assistance Publique-Hôpitaux de Paris; Département de Génétique, Hôpital Necker-Enfants Malades; Paris France
| | - Raphaëlle Campait
- Assistance Publique-Hôpitaux de Paris; Département de Génétique, Hôpital Necker-Enfants Malades; Paris France
| | - Elisabet Ars
- Molecular Biology Laboratory; Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III; Barcelona Spain
| | - Damien Brackman
- Department of Pediatrics; Haukeland University Hospital; Bergen Norway
| | - Jacques Dantal
- Service de Néphrologie et Immunologie Clinique; ITERT, CHU Hôtel Dieu; Nantes France
| | | | - Maddalena Gigante
- Department of Medical and Surgical Sciences; University of Foggia; Foggia Italy
| | - Beata S. Lipska
- Department of Biology and Genetics; Medical University of Gdansk; Gdansk 80-211 Poland
| | - Aurélia Liutkus
- Service de Néphrologie et Rhumatologie Pédiatriques; Centre de référence des Maladies Rénales Rares, Hôpital Femme Mère Enfant; Bron France
| | - André Megarbane
- Unité de Génétique Médicale, Faculté de Médecine; Université Saint Joseph; Beirut Lebanon
| | - Nabil Mohsin
- Department of Nephrology; Royal Hospital; Muscat Oman
| | - Fatih Ozaltin
- Nephrogenetics Laboratory, Department of Pediatric Nephrology; Hacettepe University Faculty of Medicine; Ankara Turkey
| | - Moin A. Saleem
- Department of Paediatric Nephrology; Bristol Royal Hospital for Children, Academic Renal Unit, School of Clinical Sciences, University of Bristol; Bristol UK
| | - Franz Schaefer
- PodoNet Consortium; Division of Pediatric Nephrology, Heidelberg University Center for Pediatrics and Adolescent Medicine; Heidelberg Germany
| | - Kenza Soulami
- CHU Ibn Rochd; Service de Néphrologie Dialyse Transplantation; Casablanca Morocco
| | - Roser Torra
- Nephrology Department; Fundació Puigvert, Instituto de Investigaciones Biomédicas Sant Pau (IIB-Sant Pau), Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III; Barcelona Spain
| | - Nicolas Garcelon
- Assistance Publique-Hôpitaux de Paris; Département de Génétique, Hôpital Necker-Enfants Malades; Paris France
- Inserm U872; Institut Imagine, Hôpital Necker-Enfants Malades; Paris France
| | - Géraldine Mollet
- Inserm U983; Institut Imagine, Hôpital Necker-Enfants Malades; Paris France
- Université Paris Descartes-Sorbonne Paris Cité; Paris France
| | - Karin Dahan
- Centre de Génétique Humaine; Université Catholique de Louvain; Bruxelles Belgique
| | - Corinne Antignac
- Assistance Publique-Hôpitaux de Paris; Département de Génétique, Hôpital Necker-Enfants Malades; Paris France
- Inserm U983; Institut Imagine, Hôpital Necker-Enfants Malades; Paris France
- Université Paris Descartes-Sorbonne Paris Cité; Paris France
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16
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Kari JA, El-Desoky SM, Gari M, Malik K, Vega-Warner V, Lovric S, Bockenhauer D. Steroid-resistant nephrotic syndrome: impact of genetic testing. Ann Saudi Med 2013; 33:533-8. [PMID: 24413855 PMCID: PMC6074900 DOI: 10.5144/0256-4947.2013.533] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Mutations in several genes are known to cause steroid-resistant nephrotic syndome (SRNS), most commonly in NPHS1, NPHS2, and WT1. Our aims were to determine the frequency of mutations in these genes in children with SRNS, the response of patients with SRNS to various immunosuppressants, and the disease outcome, and to review the predictive value of genetic testing and renal biopsy result. DESIGN AND SETTINGS A retrospective review was performed of the medical records for all children with SRNS who were treated and followed-up in the Pediatric Nephrology Unit of King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia from 2002-2012. PATIENTS AND METHODS We retrospectively reviewed the medical records of children above 1 year of age, who presented with SRNS to KAUH, Jeddah, Saudi Arabia, in the 10-year interval from 2002-2012 and for whom the results of genetic testing for NPHS1, NPHS2, and WT1 were available. We compared the clinical phenotype, including response to treatment and renal outcome to genotype data. RESULTS We identified 44 children with a clinical diagnosis of SRNS in whom results of genetic testing were available. Presumably disease-causing mutations were detected in 5 children (11.4%) of which 3 (6.8%) had NPHS2 mutation and 2 (4.5%) had NPHS1 mutation. Renal biopsy revealed minimal change disease (MCD) or variants in 17 children, focal segmental glomerulosclerosis (FSGS) in 23 children, membranoproliferative changes (MPGN) in 2 children, and IgA nephropathy in another 2 children. Children with MCD on biopsy were more likely to respond to treatment than those with FSGS. None of those with an identified genetic cause showed any response to treatment. CONCLUSION The frequency of identified disease-causing mutations in children older than 1 year with SRNS presented to KAUH was 11.4%, and these patients showed no response to treatment. Initial testing for gene mutation in children with SRNS may obviate the need for biopsy, and the use of immunosuppressive treatment in children with disease due to NPHS1 or NPHS2 mutations. Renal biopsy was useful in predicting response in those without genetic mutations.
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Affiliation(s)
- Jameela A Kari
- Jameela Abdulaziz Kari, Pediatrics, King Abdulaziz University,, PO Box 13042 Jeddah 21943, Saudi Arabia, T: 966-505-677904, F: 966-22-408-8353,
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17
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Joshi S, Andersen R, Jespersen B, Rittig S. Genetics of steroid-resistant nephrotic syndrome: a review of mutation spectrum and suggested approach for genetic testing. Acta Paediatr 2013; 102:844-56. [PMID: 23772861 DOI: 10.1111/apa.12317] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/21/2013] [Accepted: 06/10/2013] [Indexed: 01/03/2023]
Abstract
UNLABELLED Identification of genes, associated mutations and genotype-phenotype correlations in steroid-resistant nephrotic syndrome (SRNS) is being translated to clinical practice through genetic testing. This review provides an update on the genes and mutations associated with SRNS along with a suggested approach for genetic testing in patients with SRNS. CONCLUSION The number of indentified genes associated with SRNS is increasing along with our understanding of their impact on treatment response and risk of recurrence. A systematic approach to genetic testing in patients with SRNS might aid the physician in selecting appropriate treatment.
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Affiliation(s)
- S Joshi
- Department of Clinical Medicine - The Department of Pediatrics; Research Laboratory-A; Aarhus University Hospital; Aarhus N Denmark
| | - R Andersen
- Department of Clinical Medicine - The Department of Pediatrics; Research Laboratory-A; Aarhus University Hospital; Aarhus N Denmark
| | - B Jespersen
- Department of Clinical Medicine - The Department of Medicine and Nephrology C; Aarhus University Hospital; Aarhus N Denmark
| | - S Rittig
- Department of Clinical Medicine - The Department of Pediatrics; Research Laboratory-A; Aarhus University Hospital; Aarhus N Denmark
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18
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A molecular genetic analysis of childhood nephrotic syndrome in a cohort of Saudi Arabian families. J Hum Genet 2013; 58:480-9. [PMID: 23595123 DOI: 10.1038/jhg.2013.27] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 03/02/2013] [Accepted: 03/21/2013] [Indexed: 02/08/2023]
Abstract
Nephrotic syndrome (NS) is a renal disease characterized by heavy proteinuria, hypoalbuminemia, edema and hyperlipidemia. Its presentation within the first 3 months of life or in multiple family members suggests an underlying inherited cause. To determine the frequency of inherited NS, 62 cases (representing 49 families with NS) from Saudi Arabia were screened for mutations in NPHS1, NPHS2, LAMB2, PLCE1, CD2AP, MYO1E, WT1, PTPRO and Nei endonuclease VIII-like 1 (NEIL1). We detected likely causative mutations in 25 out of 49 families studied (51%). We found that the most common genetic cause of NS in our cohort was a homozygous mutation in the NPHS2 gene, found in 11 of the 49 families (22%). Mutations in the NPHS1 and PLCE1 genes allowed a molecular genetic diagnosis in 12% and 8% of families, respectively. We detected novel MYO1E mutations in three families (6%). No mutations were found in WT1, PTPRO or NEIL1. The pathogenicity of novel variants was analyzed by in silico tests and by genetic screening of ethnically matched control populations. This is the first report describing the molecular genetics of NS in the Arabian Peninsula.
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19
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Gigante M, Piemontese M, Gesualdo L, Iolascon A, Aucella F. Molecular and genetic basis of inherited nephrotic syndrome. Int J Nephrol 2011; 2011:792195. [PMID: 21904677 PMCID: PMC3167185 DOI: 10.4061/2011/792195] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 06/16/2011] [Accepted: 06/16/2011] [Indexed: 12/26/2022] Open
Abstract
Nephrotic syndrome is an heterogeneous disease characterized by increased permeability of the glomerular filtration barrier for macromolecules. Podocytes, the visceral epithelial cells of glomerulus, play critical role in ultrafiltration of plasma and are involved in a wide number of inherited and acquired glomerular diseases. The identification of mutations in nephrin and other podocyte genes as causes of genetic forms of nephrotic syndrome has revealed new important aspects of the pathogenesis of proteinuric kidney diseases and expanded our knowledge of the glomerular biology. Moreover, a novel concept of a highly dynamic slit diaphragm proteins is emerging. The most significant discoveries in our understanding of the structure and function of the glomerular filtration barrier are reviewed in this paper.
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Affiliation(s)
- Maddalena Gigante
- Division of Nephrology, Department of Biomedical Science, University of Foggia, 71121 Foggia, Italy
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20
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Piscione TD, Licht C. Genetics of proteinuria: an overview of gene mutations associated with nonsyndromic proteinuric glomerulopathies. Adv Chronic Kidney Dis 2011; 18:273-89. [PMID: 21782134 DOI: 10.1053/j.ackd.2011.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2011] [Revised: 06/02/2011] [Accepted: 06/16/2011] [Indexed: 02/08/2023]
Abstract
Heritable causes of proteinuria are rare and account for a relatively small proportion of all cases of proteinuria affecting children and adults. Yet, significant contributions to understanding the mechanistic basis for proteinuria have been made through genetic and molecular analyses of a small group of syndromic and nonsyndromic proteinuric disorders which are caused by mutations encoding structural components of the glomerular filtration barrier. Technological advances in genomic analyses and improved accessibility to mutational screening at clinically approved laboratories have facilitated diagnosis of proteinuria in the clinical setting. From a clinical standpoint, it may be argued that a genetic diagnosis mitigates exposure to potentially ineffective and harmful treatments in instances where a clear genotype-phenotype correlation exists between a specific gene mutation and treatment nonresponsiveness. However, cautious interpretation of risk may be necessitated in cases with phenotypic heterogeneity (eg, variability in clinical or histological presentation). This review summarizes gene mutations which are known to be associated with proteinuric glomerulopathies in children and adults.
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21
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Santín S, Bullich G, Tazón-Vega B, García-Maset R, Giménez I, Silva I, Ruíz P, Ballarín J, Torra R, Ars E. Clinical utility of genetic testing in children and adults with steroid-resistant nephrotic syndrome. Clin J Am Soc Nephrol 2011; 6:1139-48. [PMID: 21415313 DOI: 10.2215/cjn.05260610] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND OBJECTIVES The increasing number of podocyte-expressed genes implicated in steroid-resistant nephrotic syndrome (SRNS), the phenotypic variability, and the uncharacterized relative frequency of mutations in these genes in pediatric and adult patients with SRNS complicate their routine genetic analysis. Our aim was to compile the clinical and genetic data of eight podocyte genes analyzed in 110 cases (125 patients) with SRNS (ranging from congenital to adult onset) to provide a genetic testing approach. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Mutation analysis was performed by sequencing the NPHS1, NPHS2, TRPC6, CD2AP, PLCE1, INF2, WT1 (exons 8 and 9), and ACTN4 (exons 1 to 10) genes. RESULTS We identified causing mutations in 34% (37/110) of SRNS patients, representing 67% (16/24) familial and 25% (21/86) sporadic cases. Mutations were detected in 100% of congenital-onset, 57% of infantile-onset, 24 and 36% of early and late childhood-onset, 25% of adolescent-onset, and 14% of adult-onset patients. The most frequently mutated gene was NPHS1 in congenital onset and NPHS2 in the other groups. A partial remission was observed in 7 of 26 mutation carriers treated with immunosuppressive agents and/or angiotensin-converting enzyme inhibitors. Patients with NPHS1 mutations showed a faster progression to ESRD than patients with NPHS2 mutations. None of these mutation carriers relapsed after kidney transplantation. CONCLUSIONS We propose a genetic testing algorithm for SRNS based on the age at onset and the familial/sporadic status. Mutation analysis of specific podocyte-genes has a clinical value in all age groups, especially in children.
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Affiliation(s)
- Sheila Santín
- Molecular Biology Laboratory, Fundació Puigvert, Universitat Autònoma de Barcelona, REDinREN, Instituto de Investigación Carlos III, Barcelona, Spain
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22
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Al-Hamed M, Sayer JA, Al-Hassoun I, Aldahmesh MA, Meyer B. A novel mutation in NPHS2 causing nephrotic syndrome in a Saudi Arabian family. NDT Plus 2010; 3:545-8. [PMID: 25949463 PMCID: PMC4421432 DOI: 10.1093/ndtplus/sfq149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Accepted: 07/20/2010] [Indexed: 11/21/2022] Open
Abstract
We report a consanguineous family from Saudi Arabia with three affected children presenting with infantile nephrotic syndrome. In order to provide a molecular diagnosis, a genome-wide SNP analysis of the affected patients was performed. We identified a region of homozygosity on chromosome 1, containing the NPHS2 gene. Direct sequencing, by exon PCR, of NPHS2 identified a homozygous nucleotide change 385C > T within exon 3 in the three affected children, leading to a premature stop codon (Q129X). This homozygous truncating mutation in NPHS2 is novel and was associated with a severe clinical phenotype. Additional mutations in related genes NPHS1, PLCE1 and NEPH1 were not identified, excluding tri-allelism within these genes in this family.
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Affiliation(s)
- Mohamed Al-Hamed
- King Faisal Specialist Hospital and Research Centre , Department of Genetics, Riyadh , Saudi Arabia ; Institute of Human Genetics, International Centre of Life, Newcastle University , Central Parkway, Newcastle upon Tyne, NE1 3BZ UK
| | - John A Sayer
- Institute of Human Genetics, International Centre of Life, Newcastle University , Central Parkway, Newcastle upon Tyne, NE1 3BZ UK
| | - Ibrahim Al-Hassoun
- King Faisal Specialist Hospital and Research Centre , Department of Genetics, Riyadh , Saudi Arabia
| | - Mohamed A Aldahmesh
- King Faisal Specialist Hospital and Research Centre , Department of Genetics, Riyadh , Saudi Arabia
| | - Brian Meyer
- King Faisal Specialist Hospital and Research Centre , Department of Genetics, Riyadh , Saudi Arabia
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Santín S, Tazón-Vega B, Silva I, Cobo MÁ, Giménez I, Ruíz P, García-Maset R, Ballarín J, Torra R, Ars E. Clinical value of NPHS2 analysis in early- and adult-onset steroid-resistant nephrotic syndrome. Clin J Am Soc Nephrol 2010; 6:344-54. [PMID: 20947785 DOI: 10.2215/cjn.03770410] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND OBJECTIVES To date, very few cases with adult-onset focal segmental glomerulosclerosis (FSGS) carrying NPHS2 variants have been described, all of them being compound heterozygous for the p.R229Q variant and one pathogenic mutation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Mutation analysis was performed in 148 unrelated Spanish patients, of whom 50 presented with FSGS after 18 years of age. Pathogenicity of amino acid substitutions was evaluated through an in silico scoring system. Haplotype analysis was carried out using NPHS2 single nucleotide polymorphism and microsatellite markers. RESULTS Compound heterozygous or homozygous NPHS2 pathogenic mutations were identified in seven childhood-onset steroid-resistant nephrotic syndrome (SRNS) cases. Six additional cases with late childhood- and adult-onset SRNS were compound heterozygotes for p.R229Q and one pathogenic mutation, mostly p.A284V. p.R229Q was more frequent among SRNS cases relative to controls (odds ratio=2.65; P=0.02). Significantly higher age at onset of the disease and slower progression to ESRD were found in patients with one pathogenic mutation plus the p.R229Q variant in respect to patients with two NPHS2 pathogenic mutations. CONCLUSIONS NPHS2 analysis has a clinical value in both childhood- and adult-onset SRNS patients. For adult-onset patients, the first step should be screening for p.R229Q and, if positive, for p.A284V. These alleles are present in conserved haplotypes, suggesting a common origin for these substitutions. Patients carrying this specific NPHS2 allele combination did not respond to corticoids or immunosuppressors and showed FSGS, average 8-year progression to ESRD, and low risk for recurrence of FSGS after kidney transplant.
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Affiliation(s)
- Sheila Santín
- Fundació Puigvert, Cartagena 340-350, 08025 Barcelona, Spain
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Godefroid N, Dahan K. Expanding the clinical spectrum of congenital nephrotic syndrome caused by NPHS1 mutations. Nephrol Dial Transplant 2010; 25:2837-9. [DOI: 10.1093/ndt/gfq434] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Lo WY, Chen SY, Wang HJ, Shih HC, Chen CH, Tsai CH, Tsai FJ. Association between genetic polymorphisms of the NPHS1 gene and membranous glomerulonephritis in the Taiwanese population. Clin Chim Acta 2010; 411:714-8. [PMID: 20138859 DOI: 10.1016/j.cca.2010.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 02/01/2010] [Accepted: 02/01/2010] [Indexed: 11/26/2022]
Abstract
BACKGROUND Membranous glomerulonephritis (MGN) is one of the most common causes of nephrotic syndrome in adults. NPHS1 encoding nephrin is a transmembrane protein of the immunoglobulin family. We clarified the relationship between NPHS1 gene polymorphisms and the susceptibility or progression of MGN. METHODS We recruited a cohort of 132 biopsy-diagnosed MGN patients and 257 healthy subjects. Genotyping of three SNPs (rs401824, rs437168 and rs3814995) at chromosome positions 41034749 (5'UTR), 41026259(exon17) and 41034052 (exon 3) was performed using a Taqman SNP genotyping assay. RESULTS There was a significant difference in genotype frequency distribution of rs437168 polymorphism between MGN patients and controls. The results also showed that the frequency of the G allele was significantly higher in the patient group. Among the polymorphisms rs437168, rs401824 and rs3814995, no significant haplotype was shown in MGN patients. A stratified analysis revealed that a high disease progression in the AA genotype of rs401824 and GG genotype of rs437168 patients were associated with a low rate of remission. CONCLUSIONS The presence of the different genotypes of NPHS1 was associated with susceptibility of MGN and the remission of proteinuria during disease progression after the therapy.
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Affiliation(s)
- Wan-Yu Lo
- Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan.
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Nephrin mutations cause childhood- and adult-onset focal segmental glomerulosclerosis. Kidney Int 2009; 76:1268-76. [PMID: 19812541 DOI: 10.1038/ki.2009.381] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mutations in the NPHS1 gene cause congenital nephrotic syndrome of the Finnish type presenting before the first 3 months of life. Recently, NPHS1 mutations have also been identified in childhood-onset steroid-resistant nephrotic syndrome and milder courses of disease, but their role in adults with focal segmental glomerulosclerosis remains unknown. Here we developed an in silico scoring matrix to evaluate the pathogenicity of amino-acid substitutions using the biophysical and biochemical difference between wild-type and mutant amino acid, the evolutionary conservation of the amino-acid residue in orthologs, and defined domains, with the addition of contextual information. Mutation analysis was performed in 97 patients from 89 unrelated families, of which 52 presented with steroid-resistant nephrotic syndrome after 18 years of age. Compound heterozygous or homozygous NPHS1 mutations were identified in five familial and seven sporadic cases, including one patient 27 years old at onset of the disease. Substitutions were classified as 'severe' or 'mild' using this in silico approach. Our results suggest an earlier onset of the disease in patients with two 'severe' mutations compared to patients with at least one 'mild' mutation. The finding of mutations in a patient with adult-onset focal segmental glomerulosclerosis indicates that NPHS1 analysis could be considered in patients with later onset of the disease.
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Abstract
Congenital nephrotic syndrome (CNS) is a rare kidney disorder characterized by heavy proteinuria, hypoproteinemia, and edema starting soon after birth. The majority of cases are caused by genetic defects in the components of the glomerular filtration barrier, especially nephrin and podocin. CNS may also be a part of a more generalized syndrome or caused by a perinatal infection. Immunosuppressive medication is not helpful in the genetic forms of CNS, and kidney transplantation is the only curative therapy. Before the operation, management of these infants largely depends on the magnitude of proteinuria. In severe cases, daily albumin infusions are required to prevent life-threatening edema. The therapy also includes hypercaloric diet, thyroxin and mineral substitution, prevention of thrombotic episodes, and prompt management of infectious complications. The outcome of CNS patients without major extrarenal manifestations is comparable with other patient groups after kidney transplantation.
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Tonna SJ, Needham A, Polu K, Uscinski A, Appel GB, Falk RJ, Katz A, Al-Waheeb S, Kaplan BS, Jerums G, Savige J, Harmon J, Zhang K, Curhan GC, Pollak MR. NPHS2 variation in focal and segmental glomerulosclerosis. BMC Nephrol 2008; 9:13. [PMID: 18823551 PMCID: PMC2569023 DOI: 10.1186/1471-2369-9-13] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 09/29/2008] [Indexed: 11/10/2022] Open
Abstract
Background Focal and segmental glomerulosclerosis (FSGS) is the most common histologic pattern of renal injury seen in adults with idiopathic proteinuria. Homozygous or compound heterozygous mutations in the podocin gene NPHS2 are found in 10–30% of pediatric cases of steroid resistant nephrosis and/or FSGS. Methods We studied the spectrum of genetic variation in 371 individuals with predominantly late onset FSGS (mean age of onset 25 years) by analysis of DNA samples. Results We identified 15 non-synonymous alleles that changed the amino acid sequence in 63 of the subjects screened (17%). Eight of these (p.R138Q, p.V180M, p.R229Q, p.E237Q, p.A242V, p.A284V, p.L327F and the frameshift 855–856 delAA) are alleles previously reported to cause FSGS in either the homozygous or compound heterozygous states, while the remaining 7 (p.R10T, p.V127W, p.Q215X, p.T232I, p.L270F, p.L312V and the frameshift 397delA) are novel alleles that have not been demonstrated previously. Twelve individuals of the 371 (3.2%) screened had two likely disease-causing NPHS2 alleles, present in either a homozygous or compound heterozygous state. We genotyped the two most common of the non-synonymous NPHS2 alleles (p.A242V and p.R229Q) identified by resequencing in participants from the Nurses' Health Study and also genotyped p.R229Q in 3 diabetic cohorts. We found that the presence of either of these variants does not significantly alter the risk of albuminuria in the Nurses' Health participants, nor does p.R229Q associate with "diabetic nephropathy". Conclusion NPHS2 mutations are a rare cause of FSGS in adults. The most common non-synonymous NPHS2 variants, p.R229Q and p.A242V, do not appear to alter the risk of proteinuria in the general population nor does p.R229Q associate with measures of kidney dysfunction in diabetic individuals. Our results help clarify the frequency of FSGS-causing NPHS2 mutations in adults and broaden our understanding of the spectrum of NPHS2 mutations that lead to human disease.
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Affiliation(s)
- Stephen J Tonna
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
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Philippe A, Nevo F, Esquivel EL, Reklaityte D, Gribouval O, Tête MJ, Loirat C, Dantal J, Fischbach M, Pouteil-Noble C, Decramer S, Hoehne M, Benzing T, Charbit M, Niaudet P, Antignac C. Nephrin mutations can cause childhood-onset steroid-resistant nephrotic syndrome. J Am Soc Nephrol 2008; 19:1871-8. [PMID: 18614772 DOI: 10.1681/asn.2008010059] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Classically, infants with mutations in NPHS1, which encodes nephrin, present with nephrotic syndrome within the first 3 mo of life (congenital nephrotic syndrome of the Finnish-type), and children with mutations in NPHS2, which encodes podocin, present later with steroid-resistant nephrotic syndrome. Recently, however, NPHS2 mutations have been identified in children with congenital nephrotic syndrome. Whether NPHS1 mutations similarly account for some cases of childhood steroid-resistant nephrotic syndrome is unknown. In this study, 160 patients who belonged to 142 unrelated families and presented with nephrotic syndrome at least 3 mo after birth were screened for NPHS1 variants once mutations in NPHS2 had been excluded. Compound heterozygous NPHS1 mutations were identified in one familial case and nine sporadic cases. Mutations included protein-truncating nonsense and frameshift mutations, as well as splice-site and missense variants. Mutations were classified as "severe" or "mild" using prediction algorithms and functional assays. Most missense variants trafficked normally to the plasma membrane and maintained the ability to form nephrin homodimers and to heterodimerize with NEPH1, suggesting retained function. The presence of at least one "mild" mutation in these patients likely explains the later onset and milder course of disease. These results broaden the spectrum of renal disease related to nephrin mutations.
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Berdeli A, Mir S, Yavascan O, Serdaroglu E, Bak M, Aksu N, Oner A, Anarat A, Donmez O, Yildiz N, Sever L, Tabel Y, Dusunsel R, Sonmez F, Cakar N. NPHS2 (podicin) mutations in Turkish children with idiopathic nephrotic syndrome. Pediatr Nephrol 2007; 22:2031-40. [PMID: 17899208 DOI: 10.1007/s00467-007-0595-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Revised: 07/10/2007] [Accepted: 07/13/2007] [Indexed: 10/22/2022]
Abstract
The podocin (NPHS2) gene encodes podocin protein, which has an important role in glomerular ultrafiltration and controlling slit membrane permeability. The detection of an NPHS2 mutation affects the treatment plan for children with nephritic syndrome (NS). The frequency and spectrum of podocin mutations in the Turkish population have remained largely unknown. The aim of this study was to screen for podocin mutations in Turkish patients with steroid-resistant NS (SRNS) and to compare it with other published series. There were 295 children with SRNS, originating from Turkey, included in this study. Forty-one patients (13.8%) had familial NS and 254 patients (86.2%) had sporadic NS. Mutation analysis was performed in all eight exons of the NPHS2 gene with the direct DNA sequencing method. There were 53 different pathogenetic NPHS2 mutations detected, including 37 novel mutations. The mutation detection rate was 24.7% for all patients, 29.2% for familial, and 24% for sporadic SRNS. The most common mutated exon was exon 5 (52 allele). The presence of mutations in exon 4 was found to increase the risk of end-stage renal disease (ESRD). Among patients with mutations, the rates of renal failure and/or ESRD (26%) were significantly higher than in those without mutations (12.6%). The mean time of progression to renal failure and ESRD in patients with mutations (1.8 +/- 2.5 years) was significantly shorter than in patients without mutations (3.7 +/- 4.0 years). Additionally, in patients with heterozygote mutations, fewer cases (13.6%) progressed to renal failure and/or ESRD than in with patients who had homozygote/compound heterozygote mutations (31.3%). In conclusion, podocin mutations are responsible for some of both familial and sporadic SRNS cases in Turkey. The mutations in this gene should be searched for in every child after presentation with the first episode of NS.
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Affiliation(s)
- Afig Berdeli
- Department of Molecular Genetics, Ege University Faculty of Medicine, Izmir, Turkey.
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Niaudet P. Utility of genetic screening in children with nephrotic syndrome presenting during the first year of life. NATURE CLINICAL PRACTICE. NEPHROLOGY 2007; 3:472-3. [PMID: 17622228 DOI: 10.1038/ncpneph0560] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Accepted: 06/01/2007] [Indexed: 05/16/2023]
Affiliation(s)
- Patrick Niaudet
- Pediatric Nephrology, Hôpital Necker-Enfants Malades, Université Paris V-René Descartes, Paris, France.
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Hinkes BG, Mucha B, Vlangos CN, Gbadegesin R, Liu J, Hasselbacher K, Hangan D, Ozaltin F, Zenker M, Hildebrandt F. Nephrotic syndrome in the first year of life: two thirds of cases are caused by mutations in 4 genes (NPHS1, NPHS2, WT1, and LAMB2). Pediatrics 2007; 119:e907-19. [PMID: 17371932 DOI: 10.1542/peds.2006-2164] [Citation(s) in RCA: 288] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES Mutations in each of the NPHS1, NPHS2, WT1, and LAMB2 genes have been implicated in nephrotic syndrome, manifesting in the first year of life. The relative frequency of causative mutations in these genes in children with nephrotic syndrome manifesting in the first year of life is unknown. Therefore, we analyzed all 4 of the genes jointly in a large European cohort of 89 children from 80 families with nephrotic syndrome manifesting in the first year of life and characterized genotype/phenotype correlations. METHODS We performed direct exon sequencing of NPHS1, NPHS2, and the relevant exons 8 and 9 of WT1, whereas the LAMB2 gene was screened by enzymatic mismatches cleavage. RESULTS We detected disease-causing mutations in 66.3% (53 of 80) families (NPHS1, NPHS2, WT1, and LAMB2: 22.5%, 37.5%, 3.8%, and 2.5%, respectively). As many as 84.8% of families with congenital onset (0-3 months) and 44.1% with infantile onset (4-12 months) of nephrotic syndrome were explained by mutations. NPHS2 mutations were the most frequent cause of nephrotic syndrome among both families with congenital nephrotic syndrome (39.1%) and infantile nephrotic syndrome (35.3%), whereas NPHS1 mutations were solely found in patients with congenital onset. Of 45 children in whom steroid treatment was attempted, only 1 patient achieved a lasting response. Of these 45 treated children, 28 had causative mutations, and none of the 28 responded to treatment. CONCLUSIONS First, two thirds of nephrotic syndrome manifesting in the first year of life can be explained by mutations in 4 genes only (NPHS1, NPHS2, WT1, or LAMB2). Second, NPHS1 mutations occur in congenital nephrotic syndrome only. Third, infants with causative mutations in any of the 4 genes do not respond to steroid treatment; therefore, unnecessary treatment attempts can be avoided. Fourth, there are most likely additional unknown genes mutated in early-onset nephrotic syndrome.
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Affiliation(s)
- Bernward G Hinkes
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
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Mao J, Zhang Y, Du L, Dai Y, Gu W, Liu A, Shang S, Liang L. NPHS1 and NPHS2 gene mutations in Chinese children with sporadic nephrotic syndrome. Pediatr Res 2007; 61:117-22. [PMID: 17211152 DOI: 10.1203/01.pdr.0000250041.19306.3d] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Recent discoveries indicate that the molecules in glomerular podocytes and slit diaphragms may play an important role in the development of proteinuria and nephrotic syndrome. Mutational analyses of NPHS1 and NPHS2 were performed to verify this hypothesis in sporadic nephrotic syndrome (NS) patients. Clinical characteristics and DNA samples were collected from 38 Chinese children with sporadic steroid-sensitive NS, 22 with steroid-resistant NS and 30 controls. Direct sequencing was performed after PCR amplification of all 29 and 8 exons of the NPHS1 and NPHS2 genes, respectively. In NPHS1, 4 patients had heterozygous missense mutations leading to amino acid substitutions (R800C, Q453R). Furthermore, 3 known single nucleotide polymorphism (SNP) were found (T741T, V763V, S1105S). In NPHS2, 3 patients had novel heterozygous allelic variants leading to amino acid substitutions (S206I, E188D), while 1 patient was found to carry a novel nonsense mutation leading to a truncated protein product (Glu237STOP). Two known polymorphisms were also found (A318A, L346L). The results demonstrate that NPHS1 and NPHS2 mutations are also present in Chinese sporadic NS patients, suggesting that genetic changes of nephrin and podocin may play pathogenetic roles in some patients with sporadic steroid resistant NS.
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Affiliation(s)
- Jianhua Mao
- Department of Nephrology, Zhejiang University School of Medicine, Children's Hospital, Hangzhou 310006, Zhejiang Province, PR China
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Meyrier A. Mechanisms of disease: focal segmental glomerulosclerosis. ACTA ACUST UNITED AC 2006; 1:44-54. [PMID: 16932363 DOI: 10.1038/ncpneph0025] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 08/23/2005] [Indexed: 12/28/2022]
Abstract
Focal segmental glomerulosclerosis (FSGS), a subtype of "idiopathic nephrotic syndrome", is not a single disease, but a lesion that initially affects the glomerulus followed by the tubulointerstitium and renal vessels. The term 'FSGS' does not accurately encompass the various pathologic features of the glomerulus, which are not always focal, segmental or sclerotic. Particular variants of FSGS, such as collapsing glomerulopathy and the glomerular tip lesion, exemplify the nosologic uncertainty inherent in the classification of glomerular lesions. Pathologic variation notwithstanding, all pathologic processes that affect the podocyte lead to one of the histologic subtypes of FSGS. This specialized cell type has essential roles in maintaining the integrity of glomerular architecture, resisting endocapillary hydraulic pressure and hindering egress of proteins into the urinary space. Once initiated, podocyte lesions and ensuing fibrosis are usually irreversible, at least in human forms of FSGS. Remarkable progress has been made in unraveling the mechanisms of podocyte dysregulation that accompany the cellular variants of FSGS and in identifying genetic mutations affecting proteins of the slit diaphragm. Hopefully, this progress will drastically improve treatments for what is one of the most difficult therapeutic challenges to confront the nephrologist.
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Affiliation(s)
- Alain Meyrier
- Department of Nephrology, Hospital Georges Pompidou, Université Paris-Descartes, Faculté de Médecine, 20 Rue Leblanc, 75015 Paris, France.
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Weber S, Tönshoff B. Recurrence of focal-segmental glomerulosclerosis in children after renal transplantation: clinical and genetic aspects. Transplantation 2006; 80:S128-34. [PMID: 16286890 DOI: 10.1097/01.tp.0000187110.25512.82] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Focal segmental glomerulosclerosis (FSGS) is the primary renal disease in approximately one-tenth of pediatric patients receiving a renal allograft. Recurrence of proteinuria after renal transplantation is observed in approximately 30% of patients and negatively impacts graft survival. Risk factors for recurrence are a chronological age <15 years at onset of the nephrotic syndrome and a rapid progression of the disease in the native kidneys leading to end-stage renal disease in less than 3 years. Mesangial proliferation in the native kidneys is also an important negative predictive factor for disease recurrence. With rapid recurrence of FSGS and loss of the allograft, further renal transplants also carry a high likelihood of FSGS recurrence. Different pathogenic factors have been discussed for the recurrence of proteinuria/FSGS in the transplanted kidney, especially the involvement of a proteinuric circulating factor, whose production seems to follow T-cell dysfunction. In the last decade, mutations in genes encoding podocyte proteins have been identified in different forms of hereditary FSGS. Mutations of NPHS2 were detected in 26-38% of familial autosomal recessive steroid-resistant NS (SRNS), 6-19% of sporadic cases of SRNS, and in few adult patients with FSGS. Large multicenter studies demonstrated that patients with two pathogenic NPHS2 mutations have a very low risk of recurring FSGS after renal transplantation, whereas patients with only one mutation presumably have a risk comparable to non-NPHS2 FSGS patients. The management of FSGS following renal transplantation remains controversial. Following the assumption of a putative permeability factor, several studies have suggested the efficacy of plasmapheresis in inducing remission, preferably in conjunction with high-dose cyclosporine A or cyclophosphamide. Prospective studies will be necessary to better evaluate different therapeutic approaches.
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Affiliation(s)
- Stefanie Weber
- University Children's Hospital Heidelberg, Heidelberg, Germany.
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Franceschini N, North KE, Kopp JB, McKenzie L, Winkler C. NPHS2 gene, nephrotic syndrome and focal segmental glomerulosclerosis: A HuGE review. Genet Med 2006; 8:63-75. [PMID: 16481888 DOI: 10.1097/01.gim.0000200947.09626.1c] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Nephrotic syndrome, characterized by edema, proteinuria, hyperlipidemia and low serum albumin, is a manifestation of kidney disease involving the glomeruli. Nephrotic syndrome may be caused by primary kidney disease such as focal segmental glomerulosclerosis. Mutations in the podocin gene, NPHS2, have been shown in familial and sporadic forms of steroid-resistant nephrotic syndrome, including focal segmental glomerulosclerosis. Podocin is an integral membrane protein located at the slit diaphragm of the glomerular permeability barrier. Complete information is lacking for the population frequency of some NPHS2 variants for all racial and ethnic groups. The most frequently reported variant, R229Q, is more common among European-derived populations than African-derived populations. We calculated crude odds ratios and 95% confidence intervals of childhood nephrotic syndrome and focal segmental glomerulosclerosis associated with R229Q heterozygosity using data from five studies. The R229Q variant is not associated with focal segmental glomerulosclerosis in the US population of African descent. In contrast, the R229Q variant is associated with a trend toward increased focal segmental glomerulosclerosis risk in European-derived populations, with an estimated increased risk of 20-40%. Our insight into the association between NPHS2 variants and nephrotic disease is hampered by the limitations of the existing studies, including small numbers of affected individuals and suboptimal control groups. Nevertheless, the available data suggest that large epidemiological case-control studies to examine the association between NPHS2 variants and nephrotic syndrome are warranted.
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Affiliation(s)
- Nora Franceschini
- Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, NC 27514-3628, USA
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Abstract
Nephrotic syndrome (NS) is a pathological entity characterized by massive proteinuria and has diverse etiology. Although it is one of the most common renal diseases in children, the etiological factors responsible for idiopathic NS/FSGS remain largely unknown. Previous studies had implicated a variety of factors including genetic factors, although NS is generally regarded as a sporadic disease. Familial cases of NS have however been reported periodically, and both autosomal dominant and recessive forms have been identified. Studies of familial NS/FSGS have led to the discovery of several genes that are expressed in podocytes and are associated with proteinuria. These discoveries have shifted the focus from glomerular basement membrane (GBM) to recognition of the central role of podocytes in maintaining glomerular perm selectivity and pathogenesis of NS/FSGS. Associations with various genes (NPHS1, ACTN4, NPHS2, WT-1) and linkage to several chromosomal regions (such as 19q13, 11q21, 11q24) have been reported in patients with familial NS/FSGS.
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Affiliation(s)
- Abhay N Vats
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, PA, USA.
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Lahdenkari AT, Suvanto M, Kajantie E, Koskimies O, Kestilä M, Jalanko H. Clinical features and outcome of childhood minimal change nephrotic syndrome: is genetics involved? Pediatr Nephrol 2005; 20:1073-80. [PMID: 15968559 DOI: 10.1007/s00467-005-1965-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 04/29/2005] [Accepted: 05/02/2005] [Indexed: 11/29/2022]
Abstract
The pathogenesis of minimal change nephrotic syndrome (MCNS) is still unknown. We performed a clinical and genetic evaluation of 104 adults (mean age 35 years) who presented with MCNS in childhood (mean follow-up 30 years). Clinical data and the present health status were evaluated. Also, the genes encoding the four major slit diaphragm proteins, nephrin, podocin, Neph1 and CD2-associated protein were sequenced in 38 patients with MCNS of varying severity. MCNS presented at the mean age of 5 years, and 80% of the patients relapsed 1-28 (median 3) times during childhood. The 14 subjects (14%) who had proteinuric episodes still in adulthood had a refractory disease already as children. The participants did not show a strong tendency for allergy or immune diseases, and no familial clustering of MCNS was observed. The genetic analyses revealed heterozygous amino acid changes in nephrin and podocin in 10 of the 38 patients studied. On the other hand, the genes coding for Neph1 and CD2AP were highly conserved and no amino acid substitutions were detected. In conclusion, MCNS is a multifactorial disease, in which genetics play a minor role. Allelic variants of the podocyte proteins may, however, modify the phenotype in occasional individuals.
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Affiliation(s)
- Anne-Tiina Lahdenkari
- Hospital for Children and Adolescents and Biomedicum Helsinki, University of Helsinki, Finland.
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Current World Literature. Curr Opin Nephrol Hypertens 2005. [DOI: 10.1097/01.mnh.0000172731.05865.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Nephrotic syndrome (NS) is the most frequent cause of proteinuria in children and is emerging as a leading cause of uremia. Molecular studies in families with recessive NS have led to the discovery of specialized molecules endowed in podocytes that play a role in proteinuria. This review focalizes the key position of podocin (NPHS2 gene) in this rapidly evolving field and furnishes a compendium to those involved in clinics and genetics of NS. Screening for NPHS2 mutations have been done in sporadic NS and familial cases with recessive inheritance, documenting a mutation detection rate of 45-55% in families and 8-20% in sporadic NS according to the different groups and considering all the clinical phenotypes. Almost 50 NPHS2 mutations have been reported and variants and/or non silent polymorphisms potentially involved in proteinuria were recognized. Personalized data on clinical aspects related to responsiveness to drugs, evolution to end stage renal failure and post-transplant outcome are reported. Functional studies and cell sorting experiments demonstrated retention in the endoplasmic reticulum of most mutants involving the stomatin domain. Pull-down experiments with the common R229Q polymorphism demonstrated an altered interaction with nephrin that affects the stability of the functional unit. Overall, data are here presented that underscore a major role of inherited defects of NPHS2 in NS in children (including a relevant impact in sporadic cases) and give the functional rationale for the association. A practical compendium is also given to clinicians involved in the management of NS that should modify the classic therapeutic approach.
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Affiliation(s)
- Gianluca Caridi
- Laboratory on Pathophysiology of Uremia, Istituto Giannina Gaslini, Genova, Italy
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41
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Abstract
Congenital nephrotic syndrome is present at birth or appears during the first three months of life and infantile nephrotic syndrome during the first year. Finnish type congenital nephrotic syndrome is an autosomal recessive disease. Nephrotic syndrome is present at birth, severe and does not respond to therapy. Infectious and nutritional complications are frequent. Renal function deteriorates necessitating a dialysis-transplantation program. Between age five and eight. The disease does not recur after transplantation. Diffuse mesangial sclerosis is the second cause of congenital and infantile nephrotic syndrome. It may be isolated or part of a Denys-Drash syndrome (association of the nephropathy with male pseudohermaphroditism and Wilm's tumor). Nephrotic syndrome is resistant to therapy. Renal failure develops in early childhood. Therapy is aimed to prevent oedema, denutrition, infections and thrombosis. Proteinuria does not recur after renal transplantation. Other causes are less frequent.
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Affiliation(s)
- Patrick Niaudet
- Service de néphrologie pédiatrique, hôpital Necker-Enfants-Malades, 149, rue de Sèvres, 75743 Paris cedex 15, France.
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42
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Abstract
Mutations of NPHS1, NPHS2, or WT1 may be responsible for severe forms of nephrotic syndrome in children, progressing to end-stage renal failure. Recent studies have shown that congenital nephrotic syndrome may be secondary to mutations of one of these three genes and that some patients have a digenic inheritance of NPHS1 and NPHS2 mutations. The clinical spectrum of NPHS2 mutations has broadened, with the demonstration that mutations in the respective gene podocin may be responsible for nephrotic syndrome occurring at birth, in childhood, or in adulthood. It is now well recognized that podocin mutations are found in 10%-30% of sporadic cases of steroid-resistant nephrotic syndrome with focal segmental glomerulosclerosis. Data from large cohorts indicate that the risk of recurrence of nephrotic syndrome after renal transplantation in patients with podocin mutations is very low.
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