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Kachmar J, Boyer O, Lipska-Ziętkiewicz B, Morinière V, Gribouval O, Heidet L, Balasz-Chmielewska I, Benetti E, Cloarec S, Csaicsich D, Decramer S, Gellermann J, Guigonis V, Hogan J, Bayazit AK, Melk A, Nigmatullina N, Oh J, Ozaltin F, Ranchin B, Tsimaratos M, Trautmann A, Antignac C, Schaefer F, Dorval G. Steroid-Resistant Nephrotic Syndrome due to NPHS2 Variants Is Not Associated With Posttransplant Recurrence. Kidney Int Rep 2024; 9:973-981. [PMID: 38765578 PMCID: PMC11101709 DOI: 10.1016/j.ekir.2024.01.005] [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: 09/28/2023] [Revised: 12/07/2023] [Accepted: 01/02/2024] [Indexed: 05/22/2024] Open
Abstract
Introduction Unlike idiopathic nephrotic syndrome (NS), hereditary podocytopathies are not expected to recur after kidney transplantation. However, some reports of posttransplant recurrence of NS in patients carrying variants in the NPHS2 gene have been described, notably with the p.Arg138Gln variant, which is more prevalent in Europe. The objective of this study was to assess the risk of recurrence after kidney transplantation in a large cohort of patients with biallelic NPHS2 pathogenic variants. Methods Since January 2010, 61 patients identified at Necker-Enfants Malades Hospital and 56 enrolled in the PodoNet Registry with biallelic variants in the NPHS2 gene were transplanted and were compared with 44 transplanted children with steroid-resistant NS (SRNS) without any identified pathogenic variant. Results Of the 117 patients, 23 carried the p.Arg138Gln variant in the homozygous state and 16 in the compound heterozygous state. The other 78 patients carried different variants in the homozygous (n = 44) or compound heterozygous state. Only 1 patient with NPHS2-related SRNS experienced posttransplant recurrence (median follow-up of cohort 8.5 years [2.5-15]). Conversely, 7 of 44 patients (16%) without any identified pathogenic variant recurred within a maximum of 7 days after transplantation (median follow-up 8.9 years [0.6-13.9]). Conclusion In this large cohort, the risk of patients with causative variants in the NPHS2 gene to develop NS recurrence after kidney transplantation was extremely low. This is coherent with the pathophysiology of intrinsic slit-diaphragm disease. These data are reassuring and should be considered when counselling patients, making living kidney donation, whether related or not, a safe choice.
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Affiliation(s)
- Jessica Kachmar
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
| | - Olivia Boyer
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
- Service de néphrologie pédiatrique Centre de Référence MARHEA, Hôpital Necker-Enfants Malades, Assistance publique, Hôpitaux de Paris (AP-HP), Paris, France
| | - Beata Lipska-Ziętkiewicz
- Centre for Rare Diseases and Clinical Genetics Unit, Medical University of Gdansk, Gdansk, Poland
| | - Vincent Morinière
- Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, Assistance publique, Hôpitaux de Paris (AP-HP), Paris, France
| | - Olivier Gribouval
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
| | - Laurence Heidet
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
- Service de néphrologie pédiatrique Centre de Référence MARHEA, Hôpital Necker-Enfants Malades, Assistance publique, Hôpitaux de Paris (AP-HP), Paris, France
| | - Irena Balasz-Chmielewska
- Department of Pediatrics, Nephrology and Hypertension, Medical University of Gdansk, Gdansk, Poland
| | - Elisa Benetti
- Pediatric Nephrology Unit, Padua University Hospital, Padua, Italy
| | - Sylvie Cloarec
- Service de Néphrologie-Hémodialyse pédiatrique, Centre de compétence Maladies Rénales Rares, CHRU Tours-Clocheville, Tours, France
| | - Dagmar Csaicsich
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Stéphane Decramer
- Pediatric Nephrology Unit, Toulouse University Hospital; Centre De Référence Des Maladies Rénales Rares du Sud-Ouest, SoRare; INSERM U1048, Institute of Cardiovascular and Metabolic Diseases, Toulouse, France
| | - Jutta Gellermann
- Klinik für Pädiatrie/Nephrologie, Charité Campus Virchox-Klinikum, Berlin, Germany
| | | | - Julien Hogan
- Pediatric Nephrology, Hôpital Universitaire Robert-Debré; Paris Translational Research Center for Organ Transplantation, Inserm UMR-S970, Université Paris Cité, Paris, France
| | | | - Anette Melk
- Children’s Hospital, Hannover Medical School, Hannover, Germany
| | - Nazym Nigmatullina
- National Research Center for Maternal and Child Heatlh, Astana, Kazakhstan
| | - Jun Oh
- Pediatric Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fatih Ozaltin
- Department of Pediatric Nephrology, Hacettepe University, Faculty of Medicine, Sihhiye, Ankara, Türkiye
| | - Bruno Ranchin
- Pediatric Nephrology Unit, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Université de Lyon, Lyon, France
| | - Michel Tsimaratos
- Faculté de médecine de Marseille, Université de la Méditerranée, Marseille, France
| | - Agnes Trautmann
- Department of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University of Heidelberg, Germany
| | - Corinne Antignac
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
| | - Franz Schaefer
- Department of Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University of Heidelberg, Germany
| | - Guillaume Dorval
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Imagine Institute for Genetic Diseases, Université Paris Cité, Paris, France
- Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, Assistance publique, Hôpitaux de Paris (AP-HP), Paris, France
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Vincenti F, Angeletti A, Ghiggeri GM. State of the art in childhood nephrotic syndrome: concrete discoveries and unmet needs. Front Immunol 2023; 14:1167741. [PMID: 37503337 PMCID: PMC10368981 DOI: 10.3389/fimmu.2023.1167741] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 06/21/2023] [Indexed: 07/29/2023] Open
Abstract
Nephrotic syndrome (NS) is a clinical entity characterized by proteinuria, hypoalbuminemia, and peripheral edema. NS affects about 2-7 per 100,000 children aged below 18 years old yearly and is classified, based on the response to drugs, into steroid sensitive (SSNS), steroid dependent, (SDNS), multidrug dependent (MDNS), and multidrug resistant (MRNS). Forms of NS that are more difficult to treat are associated with a worse outcome with respect to renal function. In particular, MRNS commonly progresses to end stage renal failure requiring renal transplantation, with recurrence of the original disease in half of the cases. Histological presentations of NS may vary from minimal glomerular lesions (MCD) to focal segmental glomerulosclerosis (FSGS) and, of relevance, the histological patterns do not correlate with the response to treatments. Moreover, around half of MRNS cases are secondary to causative pathogenic variants in genes involved in maintaining the glomerular structure. The pathogenesis of NS is still poorly understood and therapeutic approaches are mostly based on clinical experience. Understanding of pathogenetic mechanisms of NS is one of the 'unmet needs' in nephrology and represents a significant challenge for the scientific community. The scope of the present review includes exploring relevant findings, identifying unmet needs, and reviewing therapeutic developments that characterize NS in the last decades. The main aim is to provide a basis for new perspectives and mechanistic studies in NS.
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Affiliation(s)
- Flavio Vincenti
- Division of Nephrology, Department of Medicine and Department of Surgery, University of California San Francisco, San Francisco, CA, United States
| | - Andrea Angeletti
- Nephrology Dialysis and Transplantation, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Istituto Giannina Gaslini, Genoa, Italy
| | - Gian Marco Ghiggeri
- Nephrology Dialysis and Transplantation, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Istituto Giannina Gaslini, Genoa, Italy
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Nandlal L, Winkler CA, Bhimma R, Cho S, Nelson GW, Haripershad S, Naicker T. Causal and putative pathogenic mutations identified in 39% of children with primary steroid-resistant nephrotic syndrome in South Africa. Eur J Pediatr 2022; 181:3595-3606. [PMID: 35920919 PMCID: PMC10673688 DOI: 10.1007/s00431-022-04581-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 07/26/2022] [Accepted: 07/26/2022] [Indexed: 11/03/2022]
Abstract
There is a paucity of data identifying genetic mutations that account for the high rate of steroid-resistant nephrotic syndrome (SRNS) in a South African paediatric population. The aim was to identify causal mutations in genes implicated in SRNS within a South African paediatric population. We enrolled 118 children with primary nephrotic syndrome (NS), 70 SRNS and 48 steroid-sensitive NS. All children with SRNS underwent kidney biopsy. We first genotyped the NPHS2 gene for the p.V260E variant in all NS cases (n = 118) and controls (n = 219). To further identify additional variants, we performed whole-exome sequencing and interrogated ten genes (NPHS1, NPHS2, WT1, LAMB2, ACTN4, TRPC6, INF2, CD2AP, PLCE1, MYO1E) implicated in SRNS with histopathological features of focal segmental glomerulosclerosis (FSGS) in 56 SRNS cases and 29 controls; we also performed exome sequencing on two patients carrying the NPHS2 p.V260E mutation as positive controls. The overall detection rate of causal and putative pathogenic mutations in children with SRNS was 27/70 (39%): 15 (21%) carried the NPHS2 p.V260E causal mutation in the homozygous state, and 12 (17%) SRNS cases carried a putative pathogenic mutation in the heterozygous state in genes (INF2 (n = 8), CD2AP (n = 3) and TRPC6 (n = 1)) known to have autosomal dominant inheritance mode. NPHS2 p.V260E homozygosity was specifically associated with biopsy-proven FSGS, accounting for 24% of children of Black ethnicity (15 of 63) with steroid-resistant FSGS. No causal or putative pathogenic mutations were identified in NPHS1, WT1, LAMB2, PLCE1, MYO1E and ACTN4. We report four novel variants in INF2, PLCE1, ACTN4 and TRPC6. Conclusion: We report putative missense variants predicted to be pathogenic in INF2, CD2AP and TRPC6 among steroid-resistant-FSGS children. However, the NPHS2 p.V260E mutation is a prevalent cause of steroid-resistant FSGS among Black South African children occurring in 24% of children with SRNS. Screening all Black African children presenting with NS for NPHS2 p.V260E will provide a precision diagnosis of steroid-resistant FSGS and inform clinical management. What is Known: • Limited data is available on the genetic disparity of SNRS in a South African paediatric setting. • The high rate of steroid resistance in Black South African children with FSGS compared to other racial groups is partially explained by the founder variant NPHS2 p.V260E. What is New: • We report putative missense variants predicted to be pathogenic in INF2, CD2AP and TRPC6 among steroid-resistant FSGS children. • NPHS2 p.V260E mutation remains a prevalent cause of steroid-resistant FSGS among Black South African children, demonstrating precision diagnostic utility.
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Affiliation(s)
- Louansha Nandlal
- Discipline of Optics and Imaging, University of KwaZulu-Natal, Durban, South Africa.
| | - Cheryl A Winkler
- Basic Research Program, Molecular Genetics Epidemiology Section, Frederick National Laboratory of the National Cancer Institute, Washington, DC, USA
| | - Rajendra Bhimma
- Department of Paediatrics and Child Health, University of KwaZulu-Natal, Durban, South Africa
| | - Sungkweon Cho
- Basic Research Program, Molecular Genetics Epidemiology Section, Frederick National Laboratory of the National Cancer Institute, Washington, DC, USA
| | - George W Nelson
- Frederick National Laboratory for Cancer Research, Frederick Advanced Biomedical Computational Science, Washington, DC, USA
| | - Sudesh Haripershad
- Department of Nephrology, University of KwaZulu-Natal, Durban, South Africa
| | - Thajasvarie Naicker
- Discipline of Optics and Imaging, University of KwaZulu-Natal, Durban, South Africa
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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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Wu N, Zhu Y, Jiang W, Song Y, Yin L, Lu Y, Tao D, Liu Y, Ma Y. A novel NPHS2 mutation (c.865A > G) identified in a Chinese family with steroid-resistant nephrotic syndrome alters subcellular localization of nephrin. Genes Genomics 2022; 44:551-559. [PMID: 35099763 DOI: 10.1007/s13258-022-01220-5] [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: 11/01/2021] [Accepted: 01/16/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND NPHS2 is the causative gene of nephrotic syndrome type 2 (MIM 600995) which often clinically manifests as steroid-resistant nephrotic syndrome (SRNS). The NPHS2 gene encodes a slit diaphragm (SD) associated protein podocin. OBJECTIVE This study reported a novel disease-causing mutation of NPHS2 in a Chinese family with SRNS. We also investigated the pathogenic mechanism of the variants in this family. METHOD A Chinese family with SRNS was recruited. Whole exome sequencing was performed to screen for disease-causing mutation. Sanger sequencing was used to confirm the results. In vitro functional experiments including immunoblotting, co-immunoprecipitation and double immunofluorescence staining were performed to explore the pathogenic mechanisms of mutations. RESULTS In this family, compound heterozygous mutations of NPHS2 (c.467dupT and c.865A > G) were identified and segregated with the disease. The maternal c.865A > G was a novel variant, leading to amino acid substitution (p.K289E). In vitro functional assays indicated that c.467dupT (p.L156FfsX11) mutant lost interaction with nephrin. Both K289E and L156FfsX11 mutants showed sharply diminished plasma membrane localization. Furthermore, abnormal distribution of podocin mutants also altered the cell membrane localization of nephrin. CONCLUSION We reported a family with SRNS caused by compound heterozygous mutations of NPHS2 (c.467dupT and c.865A > G). c.865A > G (p.K289E) in NPHS2 was a novel causative variant associated with SRNS. Both variants in this family not only affected the normal cell membrane localization of podocin, but also altered the cell membrane localization of nephrin which is the major architectural protein of SD.
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Affiliation(s)
- Na Wu
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China
| | - Yingchuan Zhu
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China
| | - Wenhao Jiang
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China
| | - Yue Song
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China
| | - Lan Yin
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China
| | - Yilu Lu
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China
| | - Dachang Tao
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China
| | - Yunqiang Liu
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China
| | - Yongxin Ma
- Department of Medical Genetics, West China Hospital, Sichuan University, 1st Keyuan 4 Lu, High-Tech Zone, Chengdu, 610041, Sichuan, China.
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Mason AE, Saleem MA, Bierzynska A. A critical re-analysis of cases of post-transplantation recurrence in genetic nephrotic syndrome. Pediatr Nephrol 2021; 36:3757-3769. [PMID: 34031708 PMCID: PMC8497325 DOI: 10.1007/s00467-021-05134-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/29/2021] [Accepted: 05/12/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND Genetic defects in podocyte proteins account for up to 30% of steroid-resistant nephrotic syndrome (SRNS) in the paediatric population. Most children with genetic SRNS are resistant to immunosuppression and at high risk of progression to stage 5 chronic kidney disease. Kidney transplantation is often the treatment of choice. The possibility of post-transplantation disease recurrence in genetic SRNS remains controversial, and poses fundamental questions about disease biology. METHODS We critically evaluated the published cases of post-transplantation recurrence in genetic patients, particularly testing 'mutations' against the most recent population variant databases, in order to clarify the diagnoses, and compare the clinical courses and responses to therapy. RESULTS Biallelic pathogenic variants in NPHS1 leading to a complete absence of nephrin were the most commonly reported and best understood instance of nephrotic syndrome occurring post-transplantation. This is an immune-mediated process driven by antibody production against the novel nephrin protein in the allograft. We also identified a number of plausible reported cases of post-transplantation recurrence involving pathogenic variants in NPHS2 (8 patients, biallelic), one in WT1 (monoallelic) and one in NUP93 (biallelic). However, the mechanism for recurrence in these cases remains unclear. Other instances of recurrence in genetic disease were difficult to interpret due to differing clinical criteria, inclusion of patients without true pathogenic variants or the influence of other factors on renal outcome. CONCLUSIONS Overall, post-transplantation recurrence remains very rare in patients with genetic SRNS. It appears to occur later after transplantation than in other patients and usually responds well to plasmapheresis with a good renal outcome.
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Affiliation(s)
- Anna E Mason
- Bristol Renal, Translational Health Sciences, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
| | - Moin A Saleem
- Bristol Renal, Translational Health Sciences, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK.
| | - Agnieszka Bierzynska
- Bristol Renal, Translational Health Sciences, Bristol Medical School, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol, BS1 3NY, UK
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7
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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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Mahwish UN, Pasha M, Heera B, Raju SB, Jahan P. Implication of podocin promoter variant haplotype in south Indian diabetic kidney patients. Meta Gene 2021. [DOI: 10.1016/j.mgene.2020.100835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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9
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Zaki M, El-Shaer S, Rady S, El-Salam MA, Abd-El-Salam R, Alkashlan IA, Saber M, Mohamed S, Hassaan M, Rabie E, Amr K. Analysis of NPHS2 Gene Mutations in Egyptian Children with Nephrotic Syndrome. Open Access Maced J Med Sci 2019; 7:3145-3148. [PMID: 31949506 PMCID: PMC6953933 DOI: 10.3889/oamjms.2019.700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 09/15/2019] [Accepted: 09/16/2019] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND: Mutations in the NPHS2 genes are the main aetiology of early-onset and familial steroid-resistant nephrotic syndrome (SRNS). The pathogenic NPHS2 mutation together with the p.R229Q variant has been less described among Egyptian children. AIM: This study aims to determine the mutation of NPHS2 in children with NS and discover the role of p.R229Q variant in SRNS METHODS: The study included 53 children with NS, and 53 healthy volunteers matched in age and sex controls. The median age at disease onset was 7.3 years. Among NS cases, 31 cases had steroid-sensitive nephrotic syndrome (SSNS) and 22 children with steroid-resistant nephrotic syndrome (SRNS). Polymerase chain reaction amplification of the whole coding region of NPHS2 gene was carried out for its mutational analysis. Restriction digestion testing was carried out after PCR to determine the presence of R229Q polymorphism. Randomly selected samples were re-genotyped by two independent technicians for assessment of Quality control RESULTS: NS patients showed a significant higher frequency of heterozygous genotype GA (89.5%) compared to control group (10.5%) with increased risk of NS (OR, 12.04; 95% CI, 2.61 to55.38; p < 0.0001). Moreover, SRNS showed a significant higher frequency of GA genotype (68.2%) than the SSNS group (6.5%). The GA genotype was associated with increased risk of SRNS (OR, 31.1; 95% CI, 5.73 to 168.48; P < 0.001) and the A allele was associated with increased risk of SRNS (OR, 15.52; 95% CI, 3.325 to 72.422; P < .001). CONCLUSION: R229Q polymorphisms are associated with SRNS, and any child with SRNS should be searched for mutations in the NPHS2 gene.
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Affiliation(s)
- Moushira Zaki
- Biological Anthropology Department, Medical Research Division, National Research Centre, Cairo, Egypt
| | - Shreen El-Shaer
- Biochemistry- Faculty of Pharmacy (Girls), Al-Azhar University, Cairo, Egypt
| | - Sahar Rady
- Biochemistry- Faculty of Pharmacy (Girls), Al-Azhar University, Cairo, Egypt
| | - Manal Abd El-Salam
- Department of Pediatrics (Nephrology Unit), Faculty of Medicine (for Girls), Al-Azhar University, Cairo, Egypt
| | - Ragaa Abd-El-Salam
- Department of Pediatrics (Nephrology Unit), Faculty of Medicine (for Girls), Al-Azhar University, Cairo, Egypt
| | | | - Mohamed Saber
- Pediatric Nephrology Unite, Al-Hussein University Hospital, Cairo, Egypt
| | - Sanaa Mohamed
- Biological Anthropology Department, Medical Research Division, National Research Centre, Cairo, Egypt
| | - Mohamed Hassaan
- Slagelse Hospital, Internal Medicine Department, Slagelse, Denmark
| | - Eman Rabie
- Medical Molecular Genetics, National Research Center, Cairo, Egypt
| | - Khalda Amr
- Medical Molecular Genetics, National Research Center, Cairo, Egypt
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10
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Siji A, Karthik KN, Pardeshi VC, Hari PS, Vasudevan A. Targeted gene panel for genetic testing of south Indian children with steroid resistant nephrotic syndrome. BMC MEDICAL GENETICS 2018; 19:200. [PMID: 30458709 PMCID: PMC6245897 DOI: 10.1186/s12881-018-0714-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 11/07/2018] [Indexed: 01/10/2023]
Abstract
BACKGROUND Steroid resistant nephrotic syndrome (SRNS) is a genetically heterogeneous disease with significant phenotypic variability. More than 53 podocyte-expressed genes are implicated in SRNS which complicates the routine use of genetic screening in the clinic. Next generation sequencing technology (NGS) allows rapid screening of multiple genes in large number of patients in a cost-effective manner. METHODS We developed a targeted panel of 17 genes to determine relative frequency of mutations in south Indian ethnicity and feasibility of using the assay in a clinical setting. Twenty-five children with SRNS and 3 healthy individuals were screened. RESULTS In this study, novel variants including 1 pathogenic variant (2 patients) and 3 likely pathogenic variants (3 patients) were identified. In addition, 2 novel variants of unknown significance (VUS) in 2 patients (8% of total patients) were also identified. CONCLUSIONS The results show that genetic screening in SRNS using NGS is feasible in a clinical setting. However the panel needs to be screened in a larger cohort of children with SRNS in order to assess the utility of the customised targeted panel in Indian children with SRNS. Determining the prevalence of variants in Indian population and improvising the bioinformatics-based filtering strategy for a more accurate differentiation of pathogenic variants from those that are benign among the VUS will help in improving medical and genetic counselling in SRNS.
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Affiliation(s)
- Annes Siji
- Division of Molecular Medicine, St. John's Research Institute, Bangalore, India
| | - K N Karthik
- Division of Molecular Medicine, St. John's Research Institute, Bangalore, India
| | | | - P S Hari
- Division of Molecular Medicine, St. John's Research Institute, Bangalore, India
| | - Anil Vasudevan
- Division of Molecular Medicine, St. John's Research Institute, Bangalore, India. .,Department of Pediatric Nephrology, St. John's Medical College Hospital, Bangalore, India.
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11
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Yu SMW, Nissaisorakarn P, Husain I, Jim B. Proteinuric Kidney Diseases: A Podocyte's Slit Diaphragm and Cytoskeleton Approach. Front Med (Lausanne) 2018; 5:221. [PMID: 30255020 PMCID: PMC6141722 DOI: 10.3389/fmed.2018.00221] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/18/2018] [Indexed: 01/19/2023] Open
Abstract
Proteinuric kidney diseases are a group of disorders with diverse pathological mechanisms associated with significant losses of protein in the urine. The glomerular filtration barrier (GFB), comprised of the three important layers, the fenestrated glomerular endothelium, the glomerular basement membrane (GBM), and the podocyte, dictates that disruption of any one of these structures should lead to proteinuric disease. Podocytes, in particular, have long been considered as the final gatekeeper of the GFB. This specialized visceral epithelial cell contains a complex framework of cytoskeletons forming foot processes and mediate important cell signaling to maintain podocyte health. In this review, we will focus on slit diaphragm proteins such as nephrin, podocin, TRPC6/5, as well as cytoskeletal proteins Rho/small GTPases and synaptopodin and their respective roles in participating in the pathogenesis of proteinuric kidney diseases. Furthermore, we will summarize the potential therapeutic options targeting the podocyte to treat this group of kidney diseases.
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Affiliation(s)
- Samuel Mon-Wei Yu
- Department of Medicine, Jacobi Medical Center, Bronx, NY, United States
| | | | - Irma Husain
- Department of Medicine, James J. Peters VA Medical Center, Bronx, NY, United States
| | - Belinda Jim
- Department of Medicine, Jacobi Medical Center, Bronx, NY, United States.,Renal Division, Jacobi Medical Center, Bronx, NY, United States
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12
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Guan FJ, Peng QQ, Wang LL, Yan XB, Dong C, Jiang XH. Histone deacetylase-2 expression and activity in children with nephrotic syndrome with different glucocorticoid response. Pediatr Nephrol 2018; 33:269-276. [PMID: 29098400 DOI: 10.1007/s00467-017-3791-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 08/22/2017] [Indexed: 01/01/2023]
Abstract
BACKGROUND Glucocorticosteroid (GC) is one of the most effective drugs available for the treatment of primary nephrotic syndrome (PNS) in children. However, some patients show little or no response to GC. The purpose of our research was to observe and describe the different levels of histone deacetylase-2 (HDAC2) expression in peripheral blood lymphocytes in children with PNS compared with various responses to the GC treatment, with the primary aim to assess the correlation between HDAC2 and GC resistance in PNS children. METHODS Forty-eight patients with PNS suffering from their first attack prior to GC treatment were chosen as subjects. They were divided into two groups, those who had steroid-sensitive nephrotic syndrome (SSNS; n = 25) and those with steroid-resistant NS (SRNS; n = 23), according to their response to a 6-week course of oral prednisone. Twenty healthy children from the Physical Examination Center in the hospital served as the control group; Peripheral blood was collected at different time points prior to GC treatment and after regular therapy. RT-PCR, western blot, and enzyme-linked immunosorbent assay (ELISA) techniques were adopted to analyze HDAC2 mRNA, protein expression, and activity, respectively, in peripheral blood lymphocytes. The level of interleukin-8 (IL-8) in serum was measured by an ELISA. RESULTS Prior to GC treatment, HDAC2 expression level and activity were lower in the SRNS group than in the SSNS and control group. A statistically significant difference in HDAC2 expression and activity were observed after GC treatment between these groups, with HDAC2 expression and activity lower in the SRNS group than in the SSNS and control groups. In the SSNS group, the expression and activity of HDAC2 were higher following GC treatment than prior to GC treatment. There was a clear difference in HDAC2 expression and activity of SRNS at the different time points. No statistically significant difference was found between the two groups. The pre-treatment and post-treatment serum IL-8 levels in the SRNS group were significantly higher than those in the SSNS group. HDAC2 from children with PNS before GC treatment and after regular therapy for 6 weeks was negatively correlated with serum IL-8 level. CONCLUSION The GC effect was influenced by the HDAC2 expression and activity, leading to decreased serum IL-8 levels in children with PNS. HDAC2 seems to be one of the markers of GC resistance in children with PNS.
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Affiliation(s)
- Feng-Jun Guan
- Department of Pediatrics, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China.
| | - Qian-Qian Peng
- Xuzhou Children's Hospital, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Lin-Li Wang
- Department of Pediatrics, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Xue-Bo Yan
- Hefei National Laboratory for Physical Sciences at Microscale and Department of Neurobiology and Biophysics, School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230027, People's Republic of China
| | - Chen Dong
- Department of Pediatrics, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Xiao-Hua Jiang
- Department of Pediatrics, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
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13
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Trautmann A, Lipska-Ziętkiewicz BS, Schaefer F. Exploring the Clinical and Genetic Spectrum of Steroid Resistant Nephrotic Syndrome: The PodoNet Registry. Front Pediatr 2018; 6:200. [PMID: 30065916 PMCID: PMC6057105 DOI: 10.3389/fped.2018.00200] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 06/25/2018] [Indexed: 02/05/2023] Open
Abstract
Background: Steroid resistant nephrotic syndrome (SRNS) is a rare condition, accounting for 10-15% of all children with idiopathic nephrotic syndrome. SRNS can be caused by genetic abnormalities or immune system dysfunction. The prognosis of SRNS varies from permanent remission to progression to end-stage kidney disease, and post-transplant recurrence is common. Objectives: The PodoNet registry project aims to explore the demographics and phenotypes of immune-mediated and genetic forms of childhood SRNS, to assess genotype-phenotype correlations, to evaluate clinical management and long-term outcomes, and to search for novel genetic entities and diagnostic and prognostic biomarkers in SRNS. Methods: In 2009, an international registry for SRNS was established to collect retro- and prospective information on renal and extrarenal disease manifestations, histopathological and genetic findings and information on family history, pharmacotherapy responsiveness and long-term outcomes. To date, more than 2,000 patients have been enrolled at 72 pediatric nephrology centers, constituting the largest pediatric SRNS cohort assembled to date. Results: In the course of the project, traditional Sanger sequencing was replaced by NGS-based gene panel screening covering over 30 podocyte-related genes complemented by whole exome sequencing. These approaches allowed to establish genetic diagnoses in 24% of the patients screened, widened the spectrum of genetic disease entities presenting with SRNS phenotype (COL4A3-5, CLCN5), and contributed to the discovery of new disease causing genes (MYOE1, PTPRO). Forty two percent of patients responded to intensified immunosuppression with complete or partial remission of proteinuria, whereas 58% turned out multi-drug resistant. Medication responsiveness was highly predictive of a favorable long-term outcome, whereas the diagnosis of genetic disease was associated with a high risk to develop end-stage renal disease during childhood. Genetic SRNS forms were generally resistant to immunosuppressive treatment, justifying to avoid such pharmacotherapies altogether once a genetic diagnosis is established. Even symptomatic anti-proteinuric treatment with RAS antagonists seems to be challenging and of limited efficacy in genetic forms of SRNS. The risk of post-transplant disease recurrence was around 30% in non-genetic SRNS whereas it is negligible in genetic cases. Conclusion: In summary, the PodoNet Registry has collected detailed clinical and genetic information in a large SRNS cohort and continues to generate fundamental insights regarding demographic and etiological disease aspects, genotype-phenotype associations, the efficacy of therapeutic strategies, and long-term patient and renal outcomes including post-transplant disease recurrence.
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Affiliation(s)
- Agnes Trautmann
- Division of Pediatric Nephrology, University Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany
- *Correspondence: Agnes Trautmann
| | - Beata S. Lipska-Ziętkiewicz
- Clinical Genetics Unit, Department of Biology and Medical Genetics, Medical University of Gdańsk, Gdańsk, Poland
| | - Franz Schaefer
- Division of Pediatric Nephrology, University Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany
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14
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Deriving and understanding the risk of post-transplant recurrence of nephrotic syndrome in the light of current molecular and genetic advances. Pediatr Nephrol 2018; 33:2027-2035. [PMID: 29022104 PMCID: PMC6153493 DOI: 10.1007/s00467-017-3793-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 08/22/2017] [Indexed: 12/31/2022]
Abstract
After renal transplantation, recurrence of the original disease is the second most common cause of graft loss, after rejection. The most dramatic manifestation of this phenomenon is in patients with nephrotic syndrome (NS). NS is a descriptive term describing a clinical picture centred on proteinuria arising from damage to the glomerular filtration barrier (GFB). There are many different drivers of that damage, ranging from immune dysregulation to genetic disorders and chronic disease/infections. The main categories in childhood are "idiopathic" (presumed immune mediated) and genetic NS, with further stratification of the idiopathic group according to steroid responses. A significant proportion of patients with NS progress to established renal failure, requiring transplantation, and one of the most difficult clinical scenarios faced by nephrologists is the recurrence of the original disease in up to 50% of patients, usually rapidly post-transplant. This is thought to be the archetypal "circulating factor" disease, in which as yet unknown circulating plasma "factor(s)" in the recipient target the donor kidney. The ability to predict in advance which patients will suffer recurrence would enhance our ability to counsel patients and families, and potentially identify those patients before transplant for tailored immunosuppressive preparation. Until very recently, stratification based on clinical categorisations has been poor in being able to predict those patients in whom disease will recur, and laboratory biomarkers are yet to be adequately refined. However, by mapping our growing understanding of disease mechanisms to clinical phenotypes, and with greatly improved genetic diagnostics, we have made progress in being able to stratify patients more specifically, and allow better predictive algorithms to be developed. Using our knowledge of podocyte biology, circulating factor-induced specific biomarkers are also being tested. This review is aimed at outlining those advances, and suggesting how we can move further forward in both clinical and biological markers of disease type.
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15
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Olowu WA, Ademola A, Ajite AB, Saad YM. Childhood nephrotic syndrome in tropical Africa: then and now. Paediatr Int Child Health 2017; 37:259-268. [PMID: 28949280 DOI: 10.1080/20469047.2017.1374002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This descriptive and comparative review examines the changing epidemiology, treatment, renal and patient outcome of childhood nephrotic syndrome (NS) in tropical Africa (TpAfr). In the 1960s to 1980s, corticosteroid-resistant non-minimal change disease (nMCD) including quartan malaria nephropathy (QMN) was the dominant renal histopathology type. The overall incidence of NS was 0.35-1.34% of hospital admissions. Median age at onset of NS ranged between 4.0 and 12.0 years while the mean (SD) age range was 5.8 (3.8) to 10.3 (4.8) years across studies. The male: female ratio was 1.6:1.0. The overall mean (SD) incidence of idiopathic minimal change disease (MCD) [21.6 (18.6%)] compared with idiopathic nMCD [59.1 (25.7%)] demonstrates significant dominance of the latter (p = 0.0001). Post-1989, the following mean (SD) incidences of histopathological types were: MCD 20.4 (17.7%), focal segmental glomerulosclerosis 39.0 (26.3%), membranoproliferative glomerulonephritis 25.4 (16.8%), proliferative glomerulonephritis 16.7 (27.0%) and membranous nephropathy 7.4 (4.5%). While the mean (SD) proportion of steroid resistance (SR) [73.5 (19.2%)] was significantly greater than the mean complete remission (CR) [26.5 (19.2%)] during 1960-1989 (p=0.005), mean (SD) SR [27.4 (25.3%)] was significantly lower than mean (SD) CR [66.1 (28.0%)] post-1989 (p < 0.001). Unlike QMN, hepatitis B virus, HIV infection, sickle cell disease and systemic lupus erythematosus are now increasingly being associated with NS in TpAfr. Mean (SD) renal survival post-1989 was 58.3 (37.0%) while all-cause mortality was 9.8%. Children with NS now survive better than before, reflecting improved access to healthcare and transition to a clinical pattern favouring idiopathic NS and increased sensitivity to corticosteroids.
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Affiliation(s)
- Wasiu A Olowu
- a Paediatric Nephrology and Hypertension Unit , Obafemi Awolowo University Teaching Hospitals Complex , Ile-Ife , Nigeria.,d Department of Paediatrics , University of Maiduguri/University of Maiduguri Teaching Hospital , Maiduguri , Nigeria
| | - Adebowale Ademola
- b Department of Paediatrics , University of Ibadan/University College Hospital , Ibadan , Nigeria
| | - Adebukola B Ajite
- c Department of Paediatrics , Ekiti State University Teaching Hospital , Ado-Ekiti , Nigeria
| | - Yauba M Saad
- d Department of Paediatrics , University of Maiduguri/University of Maiduguri Teaching Hospital , Maiduguri , Nigeria
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16
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Trautmann A, Schnaidt S, Lipska-Ziętkiewicz BS, Bodria M, Ozaltin F, Emma F, Anarat A, Melk A, Azocar M, Oh J, Saeed B, Gheisari A, Caliskan S, Gellermann J, Higuita LMS, Jankauskiene A, Drozdz D, Mir S, Balat A, Szczepanska M, Paripovic D, Zurowska A, Bogdanovic R, Yilmaz A, Ranchin B, Baskin E, Erdogan O, Remuzzi G, Firszt-Adamczyk A, Kuzma-Mroczkowska E, Litwin M, Murer L, Tkaczyk M, Jardim H, Wasilewska A, Printza N, Fidan K, Simkova E, Borzecka H, Staude H, Hees K, Schaefer F. Long-Term Outcome of Steroid-Resistant Nephrotic Syndrome in Children. J Am Soc Nephrol 2017; 28:3055-3065. [PMID: 28566477 PMCID: PMC5619960 DOI: 10.1681/asn.2016101121] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 04/17/2017] [Indexed: 02/05/2023] Open
Abstract
We investigated the value of genetic, histopathologic, and early treatment response information in prognosing long-term renal outcome in children with primary steroid-resistant nephrotic syndrome. From the PodoNet Registry, we obtained longitudinal clinical information for 1354 patients (disease onset at >3 months and <20 years of age): 612 had documented responsiveness to intensified immunosuppression (IIS), 1155 had kidney biopsy results, and 212 had an established genetic diagnosis. We assessed risk factors for ESRD using multivariate Cox regression models. Complete and partial remission of proteinuria within 12 months of disease onset occurred in 24.5% and 16.5% of children, respectively, with the highest remission rates achieved with calcineurin inhibitor-based protocols. Ten-year ESRD-free survival rates were 43%, 94%, and 72% in children with IIS resistance, complete remission, and partial remission, respectively; 27% in children with a genetic diagnosis; and 79% and 52% in children with histopathologic findings of minimal change glomerulopathy and FSGS, respectively. Five-year ESRD-free survival rate was 21% for diffuse mesangial sclerosis. IIS responsiveness, presence of a genetic diagnosis, and FSGS or diffuse mesangial sclerosis on initial biopsy as well as age, serum albumin concentration, and CKD stage at onset affected ESRD risk. Our findings suggest that responsiveness to initial IIS and detection of a hereditary podocytopathy are prognostic indicators of favorable and poor long-term outcome, respectively, in children with steroid-resistant nephrotic syndrome. Children with multidrug-resistant sporadic disease show better renal survival than those with genetic disease. Furthermore, histopathologic findings may retain prognostic relevance when a genetic diagnosis is established.
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Affiliation(s)
- Agnes Trautmann
- Division of Pediatric Nephrology, University Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany
| | - Sven Schnaidt
- Institute of Medical Biometry and Informatics, University of Heidelberg, Germany
| | | | - Monica Bodria
- Dipartimento di Medicina Clinica e Sperimentale, University of Studies of Parma, Parma, Italy
- Division of Nephrology, Dialysis and Transplantation, IRCCS Giannina Gaslini, Genoa, Italy
| | - Fatih Ozaltin
- Department of Pediatric Nephrology, Nephrogenetics Laboratory and Center for Biobanking and Genomics, Hacettepe University, Ankara, Turkey
| | - Francesco Emma
- Nephrology and Dialysis Unit, Children's Hospital Bambino Gesù, Istitutio di Ricovero e Cura a Carattere Scientificio (IRCCS), Rome, Italy
| | - Ali Anarat
- Pediatric Nephrology Department, Cukurova University Medical Faculty, Adana, Turkey
| | - Anette Melk
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Marta Azocar
- Pediatric Nephrology, Hospital Luis Calvo Mackenna-Facultad de Chile, Santiago, Chile
| | - Jun Oh
- Department of Pediatric Nephrology, University Children's Hospital, Hamburg, Germany
| | - Bassam Saeed
- Department of Pediatric Nephrology, Kidney Hospital of Damascus, Damascus, Syria
| | - Alaleh Gheisari
- Pediatric Nephrology Department, Isfahan University of Medical Science, St. Al Zahra Hospital, Isfahan, Iran
| | - Salim Caliskan
- Pediatric Nephrology Department, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey
| | - Jutta Gellermann
- Clinic for Pediatric Nephrology, Charite Hospital, Berlin, Germany
| | | | | | - Dorota Drozdz
- Department of Pediatric Nephrology, Jagiellonian University Medical College, Krakow, Poland
| | - Sevgi Mir
- Department of Pediatric Nephrology, Ege University Medical Faculty, Izmir, Turkey
| | - Ayse Balat
- Department of Pediatric Nephrology, Gaziantep University Medical Faculty, Gaziantep, Turkey
| | - Maria Szczepanska
- Department of Pediatrics, Division of Dentistry, School of Medicine, Zabrze, Poland
| | - Dusan Paripovic
- Department of Pediatric Nephrology, University Children's Hospital, Belgrade, Serbia
| | | | - Radovan Bogdanovic
- Department of Pediatric Nephrology, Institute of Mother Child and Healthcare of Serbia, Belgrade, Serbia
| | - Alev Yilmaz
- Department of Pediatric Nephrology, Istanbul Medical Faculty, Istanbul, Turkey
| | - Bruno Ranchin
- Pediatric Nephrology Unit, Hôpital Femme Mere Enfant, Hospices Civils de Lyon, Lyon, France
| | - Esra Baskin
- Department of Pediatric Nephrology, Baskent University Hospital, Ankara, Turkey
| | - Ozlem Erdogan
- Department of Pediatric Nephrology, Sami Ulus Children's Hospital, Ankara, Turkey
| | - Giuseppe Remuzzi
- Clinical Research Center for Rare Diseases Aldo & Cele Daccò, IRCCS, Istituto di Ricerche Farmacologiche Mario Negri, Bergamo, Italy
- Unit of Nephrology and Dialysis, Azienda Socio Sanitaria Territoriale Papa Giovanni XXIII, Bergamo, Italy
- Department of Biomedical and Clinical Science L. Sacco, University of Milan, Milan, Italy
| | | | | | - Mieczyslaw Litwin
- Department of Pediatric Nephrology, Centrum Zdrowia Dziecka, Warsaw, Poland
| | - Luisa Murer
- Pediatric Nephrology, Dialysis and Transplant Unit, Department of Women's and Child's Health, Hospital of Padua, Padua, Italy
| | - Marcin Tkaczyk
- Pediatric Nephrology Division, Polish Mothers Memorial Hospital Research Institute, Lodz, Poland
| | - Helena Jardim
- Department of Pediatric Nephrology, Centre Hospitalar, Porto, Portugal
| | - Anna Wasilewska
- Department of Pediatric Nephrology, University Hospital, Bialystok, Poland
| | - Nikoleta Printza
- First Pediatric Department, Hippokration General Hospital, Aristotle University, Thessaloniki, Greece
| | - Kibriya Fidan
- Pediatric Nephrology Department, Gazi University Hospital, Ankara, Turkey
| | - Eva Simkova
- Department of Pediatric Nephrology, Dubai Hospital, Dubai, United Arab Emirates
| | - Halina Borzecka
- Department of Pediatric Nephrology, Medical University, Lublin, Poland; and
| | - Hagen Staude
- Department of Pediatric Nephrology, University Children's Hospital, Rostock, Germany
| | - Katharina Hees
- Institute of Medical Biometry and Informatics, University of Heidelberg, Germany
| | - Franz Schaefer
- Division of Pediatric Nephrology, University Center for Pediatrics and Adolescent Medicine, Heidelberg, Germany;
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Boyer O, Dorval G, Servais A. Hereditary Podocytopathies in Adults: The Next Generation. KIDNEY DISEASES 2017; 3:50-56. [PMID: 28868292 DOI: 10.1159/000477243] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 04/28/2017] [Indexed: 01/15/2023]
Abstract
Idiopathic nephrotic syndrome may have two underlying mechanisms: either (1) an alteration of the immune system resulting in the production of a putative circulating factor of glomerular permeability; or (2) mutations in the structural genes of the glomerular filtration barrier in which case patients are typically multidrug resistant and do not recur after transplantation. The latter forms have been recently recognized as "hereditary podocytopathies." In the past few years, positional cloning approaches that allow the identification of gene mutations underlying diseases whose pathophysiology is unknown and animal models have helped decipher the pathophysiological mechanisms of the glomerular filtration process. Recently, the advent of next-generation sequencing (NGS) techniques has greatly facilitated the identification of numerous novel causative genes in hereditary podocytopathies. Moreover, it has revealed mutations in unexpected genes and has widened the phenotypes associated with podocyte gene mutations. The list of genes mutated in hereditary podocytopathies is constantly evolving and consists to date of more than 40 genes. However, the most recently identified genes are extremely rarely mutated and may concern only a couple of families worldwide. These discoveries provided crucial insight into the pathophysiological mechanisms linking podocyte proteins to kidney function. This review will focus on monogenic podocytopathies affecting adult patients.
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Affiliation(s)
- Olivia Boyer
- Néphrologie pédiatrique, Centre de référence MARHEA, Hôpital Necker - Enfants Malades, APHP, Paris, France.,Inserm U1163, Institut Imagine, Université Paris-Descartes Sorbonne Paris Cité, Paris, France
| | - Guillaume Dorval
- Néphrologie pédiatrique, Centre de référence MARHEA, Hôpital Necker - Enfants Malades, APHP, Paris, France.,Inserm U1163, Institut Imagine, Université Paris-Descartes Sorbonne Paris Cité, Paris, France
| | - Aude Servais
- Néphrologie, Centre de référence MARHEA, Hôpital Necker - Enfants Malades, APHP, Paris, France.,Inserm U1163, Institut Imagine, Université Paris-Descartes Sorbonne Paris Cité, Paris, France
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18
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Yang F, Chen Y, Zhang Y, Qiu L, Chen Y, Zhou J. Novel NPHS1 gene mutations in a Chinese family with congenital nephrotic syndrome. J Genet 2016; 95:161-6. [PMID: 27019444 DOI: 10.1007/s12041-015-0598-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Fengjie Yang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, People's Republic of
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19
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Dhandapani MC, Venkatesan V, Rengaswamy NB, Gowrishankar K, Ekambaram S, Sengutavan P, Perumal V. Report of novel genetic variation in NPHS2 gene associated with idiopathic nephrotic syndrome in South Indian children. Clin Exp Nephrol 2016; 21:127-133. [DOI: 10.1007/s10157-016-1237-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/17/2016] [Indexed: 10/22/2022]
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20
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[NPHS2 Mutation analysis study in children with steroid-resistant nephrotic syndrome]. ACTA ACUST UNITED AC 2015; 87:31-6. [PMID: 26455708 DOI: 10.1016/j.rchipe.2015.06.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 06/15/2015] [Indexed: 11/23/2022]
Abstract
UNLABELLED Podocin is a protein located in the glomerular slit diaphragm where it takes part in the regulation of glomerular filtration. Mutations of the NPHS2 gene that codes podocin are the main cause of autosomal recessive steroid resistant nephrotic syndrome (SRNS). OBJECTIVES To identify the NPHS2 mutations in Chilean children with SRNS, and to determine the prevalence of the most common variants in a group of healthy adults. PATIENTS AND METHODS Mutation analysis of NPHS2 in 34 Chilean children with SRNS. Once the two most common variants of NPHS2 were identified, screening for these mutations was performed on 233 healthy adults. The mutation analysis was performed by the direct sequencing of the eight coding exons by polymerase chain reaction amplification. The DNA sequencing was performed using a fluorometric method, and then evaluated with SeqPilot software. The relationship between the presence of NPHS2 variants and SRNS was calculated by comparing the allele frequency between patients with SRNS and those of the healthy volunteers using the exact Fisher test. A P<.05 was considered significant. RESULTS Pathogenic NPHS2 mutations were detected in 7 (21%) of the 34 patients studied, of which 6 were heterozygotes for p.R229Q and p.A284V. The presence of p.R229Q was 2.46% in the healthy volunteers. CONCLUSIONS This study shows that p.R229Q and p.A284V are the most frequent variants in Chilean children with SRNS. It is the first time that this relationship has been reported in Chilean children. Based on this, a screening strategy is proposed for the genetic study in patients with SRNS and their families. A parallel or sequential search strategy for p.R229Q and p.A284V in these patients is proposed.
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Lu L, Sun XM, Yin Y, Huang YF, Wang M, Wan H, Wei LB, Xiao W. The amino acid mutations of the podocin in proteinuria: a meta-analysis. Ren Fail 2015. [PMID: 26211502 DOI: 10.3109/0886022x.2015.1067129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
While many previous studies have reported an association between the single-nucleotide polymorphisms (SNPs) of the podocin and proteinuria occurred, a conclusive relationship has not been defined in every oligoallelic state of amino acid (AA) mutations in podocin. In this study, we performed a meta-analysis of the published data to investigate the impact of the oligoallelic AA mutations of the podocin on proteinuria; a total 16 AA mutations were investigated for oligoallelic pathogenicity. Despite significant heterogeneity within some of the comparisons, the results revealed significantly higher risks of proteinuria in early-onset (onset age <16) individuals for five mutations (P118L, R138Q, R168H, V180M, and V260E), and in all onset ages individuals for five mutations (R138Q, G140X, R229Q, V260E, and V290M) compared to non-variant individuals. We also tested the steroid response in individuals with R229Q and E237Q. No statistically significant differences in the two mutations carrier rate were observed between steroid resistance patients and controls. No AA mutation was selected for meta-analysis on the recurrence of proteinuria after renal transplantation as lack of control data. In conclusion, our meta-analysis tested the pathogenicity of the oligoallelic AA mutations in podocin and suggested the potential causative mutations, and the alleles showing an association with protein susceptibility. The sensitivity and specificity of each causative mutation are pending further testing.
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Affiliation(s)
- Lu Lu
- a School of Traditional Chinese Medicine, Southern Medical University , Guangzhou , China
| | - Xiao-ming Sun
- a School of Traditional Chinese Medicine, Southern Medical University , Guangzhou , China
| | - Yi Yin
- a School of Traditional Chinese Medicine, Southern Medical University , Guangzhou , China .,b Department of Nephrology , Southern Medical University TCM-Integrated Hospital , Guangzhou , China .,c Department of Traditional Chinese Medicine , ZhuJiang Hospital, Southern Medical University , Guangzhou , China , and
| | - Yan-feng Huang
- a School of Traditional Chinese Medicine, Southern Medical University , Guangzhou , China .,b Department of Nephrology , Southern Medical University TCM-Integrated Hospital , Guangzhou , China
| | - Ming Wang
- c Department of Traditional Chinese Medicine , ZhuJiang Hospital, Southern Medical University , Guangzhou , China , and
| | - Heng Wan
- d Department of Endocrinology , The Third Affiliated Hospital, Southern Medical University , Guangzhou , China
| | - Lian-Bo Wei
- a School of Traditional Chinese Medicine, Southern Medical University , Guangzhou , China .,b Department of Nephrology , Southern Medical University TCM-Integrated Hospital , Guangzhou , China .,c Department of Traditional Chinese Medicine , ZhuJiang Hospital, Southern Medical University , Guangzhou , China , and
| | - Wei Xiao
- a School of Traditional Chinese Medicine, Southern Medical University , Guangzhou , China
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22
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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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23
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Caridi G, Lugani F, Dagnino M, Gigante M, Iolascon A, Falco M, Graziano C, Benetti E, Dugo M, Del Prete D, Granata A, Borracelli D, Moggia E, Quaglia M, Rinaldi R, Gesualdo L, Ghiggeri GM. Novel INF2 mutations in an Italian cohort of patients with focal segmental glomerulosclerosis, renal failure and Charcot-Marie-Tooth neuropathy. Nephrol Dial Transplant 2014; 29 Suppl 4:iv80-6. [PMID: 25165188 DOI: 10.1093/ndt/gfu071] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Mutations of INF2 represent the major cause of familial autosomal dominant (AD) focal segmental glomerulosclerosis (FSGS). A few patients present neurological symptoms of Charcot-Marie-Tooth (CMT) disease but the prevalence of the association has not been assessed yet. METHODS We screened 28 families with AD FSGS and identified 8 INF2 mutations in 9 families (32 patients overall), 3 of which were new. Mutations were in all cases localized in the diaphanous-inhibitory domain (DID) of the protein. RESULTS Clinical features associated with INF2 mutations in our patient cohort included mild proteinuria (1.55 g/L; range 1-2.5) and haematuria as a unique symptom that was recognized at a median age of 21.75 years (range 8-30). Eighteen patients developed end-stage renal disease during their third decade of life; 12 patients presented a creatinine range between 1.2 and 1.5 mg/dL and 2 were healthy at 45 and 54 years of age. CMT was diagnosed in four cases (12.5%); one of these patients presented an already known mutation on exon 2 of INF2, whereas the other patients presented the same mutation on exon 4, a region that was not previously associated with CMT. CONCLUSIONS We confirmed the high incidence of INF2 mutations in families with AD FSGS. The clinical phenotype was mild at the onset of the disease, but evolution to ESRD was frequent. The incidence of CMT has, for the first time, been calculated here to be 12.5% of mutation carriers. Our findings support INF2 gene analysis in families in which renal failure and/or neuro-sensorial defects are inherited following an AD model.
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Affiliation(s)
- Gianluca Caridi
- Laboratory on Pathophysiology of Uremia and Division of Nephrology, Dialysis, Transplantation, Istituto Giannina Gaslini, Genova, Italy
| | - Francesca Lugani
- Laboratory on Pathophysiology of Uremia and Division of Nephrology, Dialysis, Transplantation, Istituto Giannina Gaslini, Genova, Italy
| | - Monica Dagnino
- Laboratory on Pathophysiology of Uremia and Division of Nephrology, Dialysis, Transplantation, Istituto Giannina Gaslini, Genova, Italy
| | - Maddalena Gigante
- Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy
| | - Achille Iolascon
- Department of Molecular Medicine and Medical Biotechnologies, University Federico II of Naples - CEINGE - Advanced Biotechnologies, Napoli, Italy
| | - Mariateresa Falco
- Department of Molecular Medicine and Medical Biotechnologies, University Federico II of Naples - CEINGE - Advanced Biotechnologies, Napoli, Italy
| | - Claudio Graziano
- Medical Genetics Unit, Policlinico S. Orsola-Malpighi, University of Bologna, Bologna, Italy
| | - Elisa Benetti
- Nephrology, Dialysis, Transplantation Unit, Azienda Ospedaliera-University of Padova, Padova, Italy
| | - Mauro Dugo
- Nefrologia, Dialisi, Trapianti Renali, O.C. Ca' Foncello, ULSS 9, Treviso, Italy
| | - Dorella Del Prete
- Department of Medicine, Nephrology Unit, University of Padoa, Padova, Italy
| | - Antonio Granata
- Nephrology and Dialysis Unit, 'San Giovanni di Dio' Hospital, Agrigento, Italy
| | - Donella Borracelli
- Nephrology and Dialysis Unit, Ospedale Alta Val D'Elsa, Poggibonsi, Siena, Italy
| | - Elisabetta Moggia
- Nephrology and Dialysis Unit, Ospedale S. Croce e Carle, Cuneo, Italy
| | - Marco Quaglia
- Nephrology and Transplantation Unit, Department of Translational Medicine, Azienda Ospedaliero-Universitaria 'Maggiore della Carità', 'Amedeo Avogadro' University, Novara, Italy
| | - Rita Rinaldi
- Neurology Unit, Policlinico S. Orsola-Malpighi, Bologna, Italy
| | - Loreto Gesualdo
- Renal, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari, Bari, Italy
| | - Gian Marco Ghiggeri
- Laboratory on Pathophysiology of Uremia and Division of Nephrology, Dialysis, Transplantation, Istituto Giannina Gaslini, Genova, Italy
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24
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Dai Y, Yang H, Gao P, Liu WD. NPHS2 variation in Chinese southern infants with late steroid-resistant nephrotic syndrome. Ren Fail 2014; 36:1395-8. [PMID: 25112471 DOI: 10.3109/0886022x.2014.947515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Abstract NPHS2 mutations are responsible for autosomal recessive familial steroid-resistant nephrotic syndrome (SRNS) with minor glomerular abnormalities or focal segmental glomerulosclerosis (FSGS), which is characterized by early childhood onset and rapid progression to chronic renal insufficiency. This gene mutation is also responsible for an adolescent onset form of autosomal recessive familial FSGS with heavy proteinuria. Many infants with late steroid-resistant nephrotic syndrome (late SRNS) are prone to an implicated clinical and therapeutic course. The etiopathogenesis and the long-term prognosis of late SRNS remain obscure. Considering the similar steroid resistance between late and initial SRNS, analysis of NPHS2 variation was performed in 70 sporadic Chinese infants with late SRNS and 70 controls in the present study to investigate the possible role of NPHS2 gene in late SRNS. The variation analysis revealed three polymorphisms (288C > T heterozygous in exon 2, 954T > C heterozygous and homozygous, and 1038A > G heterozygous in exon 8) in 22 out of 70 patients studied. In conclusion, NPHS2 gene mutations are not a major cause of chronic renal insufficiency caused by late SRNS in Chinese southern infants.
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Affiliation(s)
- Yiheng Dai
- Department of Neonatal, South Medical University Affiliated Maternal & Child Health Hospital of Foshan , Foshan, Guang Dong , China
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25
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Jaffer A, Unnisa W, Raju DSB, Jahan P. NPHS2mutation analysis and primary nephrotic syndrome in southern Indians. Nephrology (Carlton) 2014; 19:398-403. [DOI: 10.1111/nep.12241] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Asra Jaffer
- Department of Genetics; Osmania University; Hyderabad Andhra Pradesh India
| | - Wali Unnisa
- Department of Genetics; Osmania University; Hyderabad Andhra Pradesh India
| | - DSB Raju
- Department of Nephrology; Nizam's Institute of Medical Sciences; Hyderabad Andhra Pradesh India
| | - Parveen Jahan
- Department of Genetics; Osmania University; Hyderabad Andhra Pradesh India
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26
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Lu L, Wan H, Yin Y, Feng WJ, Wang M, Zou YC, Huang B, Wang DT, Shi Y, Zhao Y, Wei LB. The p.R229Q variant of the NPHS2 (podocin) gene in focal segmental glomerulosclerosis and steroid-resistant nephrotic syndrome: a meta-analysis. Int Urol Nephrol 2014; 46:1383-93. [PMID: 24715228 DOI: 10.1007/s11255-014-0676-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 02/13/2014] [Indexed: 01/10/2023]
Abstract
While many previous studies have reported an association between the p.R229Q variant of the NPHS2 gene and focal segmental glomerulosclerosis (FSGS) or steroid-resistant nephrotic syndrome (SRNS), a conclusive relationship has not been defined. In this study, we performed a meta-analysis of the published data to investigate the impact of the p.R229Q polymorphism on FSGS and SRNS patients. Despite significant heterogeneity within some of the comparisons, the results revealed significantly higher risks of SRNS in individuals homozygous for the variant allele (OR 7.411, 95% confidence interval 1.876-29.436, p = 0.004) compared to homozygous non-variant individuals. However, the carrier rate of the p.R229Q variant was not significantly different between SRNS patients and steroid-sensitive nephrotic syndrome patients. No statistically significant differences in the p.R229Q carrier rate were observed between FSGS patients and controls or FSGS patients and patients with different pathology classifications. No notable differences in the p.R229Q carrier rate were found between patients and controls in any group with early-onset disease (onset age < 18). In conclusion, our meta-analysis suggests that for adult-onset disease (onset age > 18), the homozygous variant could be a potential predictor of hereditary nephrotic syndrome and that the p.R229Q allele cannot currently be considered a risk factor for predicting FSGS.
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Affiliation(s)
- Lu Lu
- Department of Traditional Chinese Medicine, ZhuJiang Hospital, Southern Medical University, Guangzhou, 510280, China
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27
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Brown EJ, Pollak MR, Barua M. Genetic testing for nephrotic syndrome and FSGS in the era of next-generation sequencing. Kidney Int 2014; 85:1030-8. [PMID: 24599252 PMCID: PMC4118212 DOI: 10.1038/ki.2014.48] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 01/07/2014] [Accepted: 01/09/2014] [Indexed: 12/11/2022]
Abstract
The haploid human genome is composed of three billion base pairs, about one percent of which consists of exonic regions, the coding sequence for functional proteins, also now known as the “exome”. The development of next-generation sequencing makes it possible from a technical and economic standpoint to sequence an individual’s exome but at the cost of generating long lists of gene variants that are not straightforward to interpret. Various public consortiums such as the 1000 Genomes Project and the NHLBI Exome Sequencing Project have sequenced the exomes and a subset of entire genomes of over 2500 control individuals with ongoing efforts to further catalogue genetic variation in humans.1 The use of these public databases facilitates the interpretation of these variant lists produced by exome sequencing and, as a result, novel genetic variants linked to disease are being discovered and reported at a record rate. However, the interpretation of these results and their bearing on diagnosis, prognosis, and treatment is becoming ever more complicated. Here, we discuss the application of genetic testing to individuals with focal and segmental glomerulosclerosis (FSGS), taking a historical perspective on gene identification and its clinical implications along with the growing potential of next-generation sequencing.
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Affiliation(s)
- Elizabeth J Brown
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Martin R Pollak
- Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Moumita Barua
- 1] Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts, USA [2] Department of Medicine, Toronto General Hospital, Toronto, Ontario, Canada
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28
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Laurin LP, Lu M, Mottl AK, Blyth ER, Poulton CJ, Weck KE. Podocyte-associated gene mutation screening in a heterogeneous cohort of patients with sporadic focal segmental glomerulosclerosis. Nephrol Dial Transplant 2014; 29:2062-9. [DOI: 10.1093/ndt/gft532] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
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29
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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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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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31
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Mottl AK, Lu M, Fine CA, Weck KE. A novel TRPC6 mutation in a family with podocytopathy and clinical variability. BMC Nephrol 2013; 14:104. [PMID: 23663351 PMCID: PMC3662586 DOI: 10.1186/1471-2369-14-104] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 04/05/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mutation in several podocyte-specific genes have been noted to result in phenotypic heterogeneity. Herein, we report a novel, autosomal dominant TRPC6 mutation in a family with disease ranging from asymptomatic minimal change disease to end-stage kidney disease. CASE PRESENTATION A 35 year old woman developed asymptomatic, nephrotic range proteinuria during pregnancy that did not resolve after delivery. Her mother had end-stage kidney disease of unknown etiology and her brother had asymptomatic proteinuria. Kidney biopsy revealed minimal change disease in both the proband and her brother. Genetic testing was performed in the proband and mother, revealing a novel frameshift mutation in TRPC6, D873fsX878. The proband continues to have subnephrotic range proteinuria and normal creatinine but her brother has since developed progressive chronic kidney disease. CONCLUSIONS The current case report underscores the heterogeneity of disease in podocytopathies and related genes. Genetic testing of podocyte genes is useful in order to understand the pathophysiologic processes underlying these overlapping diseases.
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Affiliation(s)
- Amy K Mottl
- University of North Carolina Kidney Center, UNC School of Medicine, Chapel Hill, NC, USA.
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32
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NPHS2 p.V290M mutation in late-onset steroid-resistant nephrotic syndrome. Pediatr Nephrol 2013; 28:751-7. [PMID: 23242530 DOI: 10.1007/s00467-012-2379-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 10/19/2012] [Accepted: 11/01/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND The most frequently mutated gene of steroid-resistant nephrotic syndrome (SRNS) is NPHS2. Current guidelines propose the sequencing of all NPHS2 exons only in childhood-onset SRNS. METHODS A cohort of 38 Hungarian patients with childhood-onset nephrotic-range proteinuria was screened for NPHS2 mutations. The frequency of the p.V290M mutation in late-onset SRNS was examined in the French and PodoNet cohorts. RESULTS Of the 38 Hungarian patients screened, seven carried NPHS2 mutations on both alleles, of whom two-diagnosed with proteinuria through school screening programs at the age of 9.7 and 14 years, respectively-did not develop nephrotic syndrome in childhood. The first, an 18-year-old boy, homozygous for p.V290M, has never developed edema. The second, a 31-year-old woman-compound heterozygous for p.V290M and p.R138Q-was first detected with hypoalbuminemia (<30 g/l) and edema at the age of 24.3 and 27.5 years, respectively. Both patients currently have a normal glomerular filtration rate. The mutation p.V290M was carried by three of the 38 patients in the Hungarian cohort, by two of the 95 patients with late-onset SRNS in the PodoNet cohort and by none of the 83 patients in the French cohort. CONCLUSIONS We propose that not only the p.R229Q variant, but also the p.V290M mutation should be screened in Central and Eastern European patients with late-onset SRNS.
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33
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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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34
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Büscher AK, Weber S. Educational paper: the podocytopathies. Eur J Pediatr 2012; 171:1151-60. [PMID: 22237399 DOI: 10.1007/s00431-011-1668-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 12/20/2011] [Indexed: 02/07/2023]
Abstract
In the recent past, hereditary podocytopathies have increasingly been recognized to be involved in the development of steroid-resistant nephrotic syndrome (SRNS). Mutations in podocyte genes substantially alter the development and structural architecture of the podocyte including its interdigitating foot processes. These constitute the basis of the slit diaphragm which is an essential part of the glomerular filtration barrier. Depending on the affected protein, the clinical course is variable with respect to onset and severity of the disease as well as treatment options. In general, hereditary podocytopathies are associated with a poorer renal outcome than the non-genetic variants. In addition, they require a different approach with respect to the applied therapeutic strategies as most patients do not respond to immunosuppressive agents. Therefore, genetic testing of podocyte genes should be considered as a routine diagnostic tool for patients with SRNS because the identification of a genetic origin has a direct implication on clinical course, renal outcome, and genetic counseling. In this educational paper, we will give an overview over the podocyte genes identified so far to be involved into the pathophysiology of hereditary podocytopathies.
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Affiliation(s)
- Anja K Büscher
- Pediatric Nephrology, Pediatrics II, University-Children's Hospital Essen, Hufelandstraße 55, 45122 Essen, Germany.
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Magnasco A, Ravani P, Edefonti A, Murer L, Ghio L, Belingheri M, Benetti E, Murtas C, Messina G, Massella L, Porcellini MG, Montagna M, Regazzi M, Scolari F, Ghiggeri GM. Rituximab in children with resistant idiopathic nephrotic syndrome. J Am Soc Nephrol 2012; 23:1117-24. [PMID: 22581994 DOI: 10.1681/asn.2011080775] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Idiopathic nephrotic syndrome resistant to standard treatments remains a therapeutic dilemma in pediatric nephrology. To test whether the anti-CD20 monoclonal antibody rituximab may benefit these patients, we conducted an open-label, randomized, controlled trial in 31 children with idiopathic nephrotic syndrome unresponsive to the combination of calcineurin inhibitors and prednisone. All children continued prednisone and calcineurin inhibitors at the doses prescribed before enrollment, and one treatment group received two doses of rituximab (375 mg/m(2) intravenously) as add-on therapy. The mean age was 8 years (range, 2-16 years). Rituximab did not reduce proteinuria at 3 months (change, -12% [95% confidence interval, -73% to 110%]; P=0.77 in analysis of covariance model adjusted for baseline proteinuria). Additional adjustment for previous remission and interaction terms (treatment by baseline proteinuria and treatment by previous remission) did not change the results. In conclusion, these data do not support the addition of rituximab to prednisone and calcineurin inhibitors in children with resistant idiopathic nephrotic syndrome.
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Affiliation(s)
- Alberto Magnasco
- Division of Nephrology, Dialysis and Transplantation and Laboratory on Pathophysiology of Uremia, Istituto G. Gaslini, Largo G. Gaslini 5, Genoa, Italy
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Rood IM, Deegens JKJ, Wetzels JFM. Genetic causes of focal segmental glomerulosclerosis: implications for clinical practice. Nephrol Dial Transplant 2012; 27:882-90. [PMID: 22334613 DOI: 10.1093/ndt/gfr771] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Focal segmental glomerulosclerosis (FSGS) is a common cause of steroid-resistant nephrotic syndrome in children and adults. Although FSGS is considered a podocyte disease, the aetiology is diverse. In recent years, many inheritable genetic forms of FSGS have been described, caused by mutations in proteins that are important for podocyte function. In the present commentary, we review these genetic causes of FSGS and describe their prevalence in familial and sporadic FSGS. In routine clinical practice, the decision to perform the costly DNA analysis should be based on the assessment if the results affect the care of the individual patient with respect to the evaluation of extra-renal manifestations, treatment decisions, transplantation and genetic counselling.
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Affiliation(s)
- Ilse M Rood
- Department of Nephrology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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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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Bertelli R, Bodria M, Nobile M, Alloisio S, Barbieri R, Montobbio G, Patrone P, Ghiggeri GM. Regulation of innate immunity by the nucleotide pathway in children with idiopathic nephrotic syndrome. Clin Exp Immunol 2011; 166:55-63. [PMID: 21762125 DOI: 10.1111/j.1365-2249.2011.04441.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Activation of the oxidative burst and failure of CD4(+) CD25(+) cell regulation have been implicated in idiopathic nephrotic syndrome (iNS). The intimate mechanism is, however, unknown and requires specifically focused studies. We investigated reactive oxygen species (ROS) generation [di-chlorofluorescein-diacetate (DCFDA)] fluorescence assay and the regulatory adenosine 5'-triphosphate (ATP) pathways in the blood of 41 children with iNS, utilizing several agonists and antagonists of nucleotide/nucleoside receptors, including the addition of soluble apyrase. The CD4(+) CD25(+) CD39(+) /CD73(+) expression was determined in vivo in parallel during disease activity. Overall, we found that the percentage of CD39(+) CD4(+) CD25(+) was reduced markedly in iNS by 80% (3·43±0·04% versus 13·14±0·07% of total lymphocytes, P<0·001). In these patients, reactive oxygen species (ROS) generation by polymorphonuclear neutrophils (PMN) at rest was a function of apyrase (CD39) expressed by CD4(+) CD25(+) , with higher rates in patients with very low CD39(+) CD4(+) CD25(+) levels (<7·5%). Addition of apyrase reduced ROS generation by 40% in both iNS and controls and was mainly effective in patients. The quota of ROS surviving ATP elimination was higher still in iNS. In vitro studies to limit ROS generation with adenosine analogues (2'-chloroadenosine and 5'-N-ethylcarboxamidoadenosine) produced minor effects. At variance, antagonizing ATP efflux with carbenoxolone or by antagonizing ATP effects (Brilliant Blue G, KN62 and A437089) reduced ROS generation comparable to apyrase. These results confirm a key role of ATP in the regulation of innate immunity and minimize the effect of adenosine. Decreased CD39(+) CD4(+) CD25(+) expression in iNS highlights an impairment of ATP degradation in this pathology. However, high ROS surviving ATP consumption implies a major role of other regulatory pathways.
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Affiliation(s)
- R Bertelli
- Division of Nephrology, Dialysis, Transplantation and Laboratory on Pathophysiology of Uremia Division of Anesthesiology, Istituto Giannina Gaslini IRCCS, Genova, Italy
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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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Exome sequencing identified MYO1E and NEIL1 as candidate genes for human autosomal recessive steroid-resistant nephrotic syndrome. Kidney Int 2011; 80:389-96. [PMID: 21697813 DOI: 10.1038/ki.2011.148] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To identify gene loci associated with steroid-resistant nephrotic syndrome (SRNS), we utilized homozygosity mapping and exome sequencing in a consanguineous pedigree with three affected siblings. High-density genotyping identified three segments of homozygosity spanning 33.6 Mb on chromosomes 5, 10, and 15 containing 296 candidate genes. Exome sequencing identified two homozygous missense variants within the chromosome 15 segment; an A159P substitution in myosin 1E (MYO1E), encoding a podocyte cytoskeletal protein; and an E181K substitution in nei endonuclease VIII-like 1 (NEIL1), encoding a base-excision DNA repair enzyme. Both variants disrupt highly conserved protein sequences and were absent in public databases, 247 healthy controls, and 286 patients with nephrotic syndrome. The MYO1E A159P variant is noteworthy, as it is expected to impair ligand binding and actin interaction in the MYO1E motor domain. The predicted loss of function is consistent with the previous demonstration that Myo1e inactivation produces nephrotic syndrome in mice. Screening 71 additional patients with SRNS, however, did not identify independent NEIL1 or MYO1E mutations, suggesting larger sequencing efforts are needed to uncover which mutation is responsible for the phenotype. Our findings demonstrate the utility of exome sequencing for rapidly identifying candidate genes for human SRNS.
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Ravani P, Magnasco A, Edefonti A, Murer L, Rossi R, Ghio L, Benetti E, Scozzola F, Pasini A, Dallera N, Sica F, Belingheri M, Scolari F, Ghiggeri GM. Short-term effects of rituximab in children with steroid- and calcineurin-dependent nephrotic syndrome: a randomized controlled trial. Clin J Am Soc Nephrol 2011; 6:1308-15. [PMID: 21566104 DOI: 10.2215/cjn.09421010] [Citation(s) in RCA: 150] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Prednisone and calcineurin inhibitors are the mainstay therapy of idiopathic nephrotic syndrome (INS) in children. However, drug dependence and toxicity associated with protracted use are common. Case series suggest that the anti-CD20 monoclonal antibody rituximab (RTX) may maintain disease remission. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This open-label randomized controlled trial was powered to show that a strategy based on RTX and lower doses of prednisone and calcineurin inhibitors was noninferior to standard doses of these agents in maintaining 3-month proteinuria as low as baseline or up to 1 g/d greater (noninferiority margin). Participants were stratified by the presence of toxicity to prednisone/calcineurin inhibitors and centrally assigned to add RTX (Mabthera, 375 mg/m(2) intravenously) to lower doses of standard agents or to continue with current therapy alone. The risk of relapse was a secondary outcome. RESULTS Fifty-four children (mean age 11 ± 4 years) with INS dependent on prednisone and calcineurin inhibitors for >12 months were randomized. Three-month proteinuria was 70% lower in the RTX arm (95% confidence interval 35% to 86%) as compared with standard therapy arm (intention-to-treat); relapse rates were 18.5% (intervention) and 48.1% (standard arm) (P = 0.029). Probabilities of being drug-free at 3 months were 62.9% and 3.7%, respectively (P < 0.001); 50% of RTX cases were in stable remission without drugs after 9 months. CONCLUSIONS Rituximab and lower doses of prednisone and calcineurin inhibitors are noninferior to standard therapy in maintaining short-term remission in children with INS dependent on both drugs and allow their temporary withdrawal.
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Affiliation(s)
- Pietro Ravani
- Division of Nephrology, University of Calgary, Calgary, Alberta, Canada
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Jungraithmayr TC, Hofer K, Cochat P, Chernin G, Cortina G, Fargue S, Grimm P, Knueppel T, Kowarsch A, Neuhaus T, Pagel P, Pfeiffer KP, Schäfer F, Schönermarck U, Seeman T, Toenshoff B, Weber S, Winn MP, Zschocke J, Zimmerhackl LB. Screening for NPHS2 mutations may help predict FSGS recurrence after transplantation. J Am Soc Nephrol 2011; 22:579-85. [PMID: 21355056 DOI: 10.1681/asn.2010010029] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Steroid-resistant focal segmental glomerulosclerosis (FSGS) often recurs after renal transplantation. In this international survey, we sought to identify genotype-phenotype correlations of recurrent FSGS. We surveyed 83 patients with childhood-onset primary FSGS who received at least one renal allograft and analyzed 53 of these patients for NPHS2 mutations. The mean age at diagnosis was 6.7 years, and the mean age at first renal transplantation was 13 years. FSGS recurred in 30 patients (36%) after a median of 13 days (range, 1.5 to 152 days). Twenty-three patients received a second kidney transplant, and FSGS recurred in 11 (48%) after a median of 16 days (range, 2.7 to 66 days). None of the 11 patients with homozygous or compound heterozygous NPHS2 mutations developed recurrent FSGS compared with 45% of patients without mutations. These data suggest that genetic testing for pathogenic mutations may be important for prognosis and treatment of FSGS both before and after transplantation.
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Trachtman H, Vento S, Gipson D, Wickman L, Gassman J, Joy M, Savin V, Somers M, Pinsk M, Greene T. Novel therapies for resistant focal segmental glomerulosclerosis (FONT) phase II clinical trial: study design. BMC Nephrol 2011; 12:8. [PMID: 21310077 PMCID: PMC3045306 DOI: 10.1186/1471-2369-12-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 02/10/2011] [Indexed: 11/10/2022] Open
Abstract
Background The lack of adequate randomized clinical trials (RCT) has hindered identification of new therapies that are safe and effective for patients with primary focal segmental glomerulosclerosis (FSGS), especially in patients who fail to respond to corticosteroids and immunosuppressive therapies. Recent basic science advances have led to development of alternative treatments that specifically target aberrant pathways of fibrosis which are relevant to disease progression in FSGS. There is a need for a flexible Phase II study design which will test such novel antifibrotic strategies in order to identify agents suitable for phase III testing. Methods/Design The Novel Therapies for Resistant Focal Segmental Glomerulosclerosis (FONT) project is a multicenter Phase I/II RCT designed to investigate the potential efficacy of novel therapies for resistant FSGS. Adalimumab and galactose will be evaluated against conservative therapy consisting of the combination of lisinopril, losartan and atorvastatin. The sample size is defined to assure that if one of the treatments has a superior response rate compared to that of the other treatments, it will be selected with high probability for further evaluation. Comparison of primary and secondary endpoints in each study arm will enable a choice to be made of which treatments are worthy of further study in future Phase III RCT. Discussion This report highlights the key features of the FONT II RCT including the two-step outcome analysis that will expedite achievement of the study objectives. The proposed phase II study design will help to identify promising agents for further testing while excluding ineffective agents. This staged approach can help to prevent large expenditures on unworthy therapeutic agents in the management of serious but rare kidney diseases Trial Registration ClinicalTrials.gov, NCT00814255
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Affiliation(s)
- Howard Trachtman
- Cohen Children's Medical Center of New York, North Shore Long Island Jewish Health System, New Hyde Park, NY, USA.
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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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Benoit G, Machuca E, Heidet L, Antignac C. Hereditary kidney diseases: highlighting the importance of classical Mendelian phenotypes. Ann N Y Acad Sci 2010; 1214:83-98. [PMID: 20969579 DOI: 10.1111/j.1749-6632.2010.05817.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A Mendelian inheritance underlies a nonnegligible proportion of hereditary kidney diseases, suggesting that the encoded proteins are essential for maintenance of the renal function. The identification of genes involved in congenital anomalies of the kidney and in familial forms of nephrotic syndrome significantly increased our understanding of the renal development and kidney filtration barrier physiology. This review will focus on the classical phenotype and clinical heterogeneity observed in the monogenic forms of these disorders. In addition, the role of susceptibility genes in kidney diseases with a complex inheritance will also be discussed.
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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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Recurrence of focal segmental glomerulosclerosis after kidney transplantation: strategies and outcome. Curr Opin Organ Transplant 2010; 15:628-32. [DOI: 10.1097/mot.0b013e32833dee3a] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Benoit G, Machuca E, Antignac C. Hereditary nephrotic syndrome: a systematic approach for genetic testing and a review of associated podocyte gene mutations. Pediatr Nephrol 2010; 25:1621-32. [PMID: 20333530 PMCID: PMC2908444 DOI: 10.1007/s00467-010-1495-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 02/04/2010] [Accepted: 02/08/2010] [Indexed: 11/30/2022]
Abstract
Several genes have been implicated in genetic forms of nephrotic syndrome occurring in children. It is now known that the phenotypes associated with mutations in these genes display significant variability, rendering genetic testing and counselling a more complex task. This review will focus on the recent clinical findings associated with those genes known to be involved in isolated steroid-resistant nephrotic syndrome in children and, thereby, propose an approach for appropriate mutational screening. The recurrence of proteinuria after transplantation in patients with hereditary forms of nephrotic syndrome will also be discussed.
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Affiliation(s)
- Geneviève Benoit
- Inserm, U983, Hôpital Necker-Enfants Malades, Paris, France ,CHU Sainte-Justine, Université de Montréal, Montréal, Canada
| | - Eduardo Machuca
- Inserm, U983, Hôpital Necker-Enfants Malades, Paris, France ,Pontificia Universidad Católica de Chile, Escuela de Medicina, Santiago, Chile
| | - Corinne Antignac
- Inserm, U983, Hôpital Necker-Enfants Malades, Paris, France ,Faculté de Médecine Paris Descartes, Université Paris Descartes, Paris, France ,Département de Génétique, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France ,Inserm, U983, 6e étage, Tour Lavoisier, Hôpital Necker-Enfants Malades, 149 rue de Sèvres, 75015 Paris, France
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Büscher AK, Kranz B, Büscher R, Hildebrandt F, Dworniczak B, Pennekamp P, Kuwertz-Bröking E, Wingen AM, John U, Kemper M, Monnens L, Hoyer PF, Weber S, Konrad M. Immunosuppression and renal outcome in congenital and pediatric steroid-resistant nephrotic syndrome. Clin J Am Soc Nephrol 2010; 5:2075-84. [PMID: 20798252 DOI: 10.2215/cjn.01190210] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
BACKGROUND AND OBJECTIVES Mutations in podocyte genes are associated with steroid-resistant nephrotic syndrome (SRNS), mostly affecting younger age groups. To date, it is unclear whether these patients benefit from intensified immunosuppression with cyclosporine A (CsA). The aim of this study was to evaluate the influence of podocyte gene defects in congenital nephrotic syndrome (CNS) and pediatric SRNS on the efficacy of CsA therapy and preservation of renal function. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS Genotyping was performed in 91 CNS/SRNS patients, irrespective of age at manifestation or response to CsA. RESULTS Mutations were identified in 52% of families (11 NPHS1, 17 NPHS2, 11 WT1, 1 LAMB2, 3 TRPC6). Sixty-eight percent of patients with nongenetic SRNS responded to CsA, most of them achieved complete remission. In contrast, none of the patients with genetic CNS/SRNS experienced a complete remission and only two (17%) achieved a partial response, both affected by a WT1 mutation. Preservation of renal function was significantly better in children with nongenetic disease after a mean follow-up time of 8.6 years (ESRD in 29% versus 71%). CONCLUSIONS The mutation detection rate in our population was high (52%). Most patients with genetic CNS/SRNS did not benefit from CsA with significantly lower response rates compared with nongenetic patients and showed rapid progression to end-stage renal failure. These data strongly support the idea not to expose CNS/SRNS patients with inherited defects related to podocyte function to intensified immunosuppression with CsA.
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Affiliation(s)
- Anja K Büscher
- Pediatric Nephrology, Pediatrics II, University of Duisburg-Essen, Essen, Germany
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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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