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Tory K. The dominant findings of a recessive man: from Mendel's kid pea to kidney. Pediatr Nephrol 2024; 39:2049-2059. [PMID: 38051388 PMCID: PMC11147900 DOI: 10.1007/s00467-023-06238-9] [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: 08/21/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023]
Abstract
The research of Mendel, born two centuries ago, still has many direct implications for our everyday clinical work. He introduced the terms "dominant" and "recessive" characters and determined their 3:1 ratio in the offspring of heterozygous "hybrid" plants. This distribution allowed calculation of the number of the phenotype-determining "elements," i.e., the alleles, and has been used ever since to prove the monogenic origin of a disorder. The Mendelian inheritance of monogenic kidney disorders is still of great help in distinguishing them from those with multifactorial origin in clinical practice. Inheritance of most monogenic kidney disorders fits to Mendel's observations: the equal contribution of the two parents and the complete penetrance or the direct correlation between the frequency of the recessive character and the degree of inbreeding. Nevertheless, beyond the truth of these basic concepts, several observations have expanded their genetic characteristics. The extreme genetic heterogeneity, the pleiotropy of the causal genes and the role of modifiers in ciliopathies, the digenic inheritance and parental imprinting in some tubulopathies, and the incomplete penetrance and eventual interallelic interactions in podocytopathies, reflect this expansion. For all these reasons, the transmission pattern in a natural setting may depend not only on the "character" but also on the causal gene and the variant. Mendel's passion for research combined with his modest personality and meticulous approach can still serve as an example in the work required to understand the non-Mendelian universe of genetics.
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Affiliation(s)
- Kálmán Tory
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.
- Pediatric Center, MTA Center of Excellence, Semmelweis University, Budapest, Hungary.
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Mitrotti A, Giliberti M, Di Leo V, di Bari I, Pontrelli P, Gesualdo L. Hidden genetics behind glomerular scars: an opportunity to understand the heterogeneity of focal segmental glomerulosclerosis? Pediatr Nephrol 2024; 39:1685-1707. [PMID: 37728640 PMCID: PMC11026212 DOI: 10.1007/s00467-023-06046-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 05/02/2023] [Accepted: 05/30/2023] [Indexed: 09/21/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS) is a complex disease which describes different kinds of kidney defects, not exclusively linked with podocyte defects. Since nephrin mutation was first described in association with early-onset nephrotic syndrome (NS), many advancements have been made in understanding genetic patterns associated with FSGS. New genetic causes of FSGS have been discovered, displaying unexpected genotypes, and recognizing possible site of damage. Many recent large-scale sequencing analyses on patients affected by idiopathic chronic kidney disease (CKD), kidney failure (KF) of unknown origin, or classified as FSGS, have revealed collagen alpha IV genes, as one of the most frequent sites of pathogenic mutations. Also, recent interest in complex and systemic lysosomal storage diseases, such as Fabry disease, has highlighted GLA mutations as possible causes of FSGS. Tubulointerstitial disease, recently classified by KDIGO based on genetic subtypes, when associated with UMOD variants, may phenotypically gain FSGS features, as well as ciliopathy genes or others, otherwise leading to completely different phenotypes, but found carrying pathogenic variants with associated FSGS phenotype. Thus, glomerulosclerosis may conceal different heterogeneous conditions. When a kidney biopsy is performed, the principal objective is to provide an accurate diagnosis. The broad spectrum of phenotypic expression and genetic complexity is demonstrating that a combined path of management needs to be applied. Genetic investigation should not be reserved only to selected cases, but rather part of medical management, integrating with clinical and renal pathology records. FSGS heterogeneity should be interpreted as an interesting opportunity to discover new pathways of CKD, requiring prompt genotype-phenotype correlation. In this review, we aim to highlight how FSGS represents a peculiar kidney condition, demanding multidisciplinary management, and in which genetic analysis may solve some otherwise unrevealed idiopathic cases. Unfortunately there is not a uniform correlation between specific mutations and FSGS morphological classes, as the same variants may be identified in familial cases or sporadic FSGS/NS or manifest a variable spectrum of the same disease. These non-specific features make diagnosis challenging. The complexity of FSGS genotypes requires new directions. Old morphological classification does not provide much information about the responsible cause of disease and misdiagnoses may expose patients to immunosuppressive therapy side effects, mistaken genetic counseling, and misguided kidney transplant programs.
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Affiliation(s)
- Adele Mitrotti
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy.
| | - Marica Giliberti
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Vincenzo Di Leo
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Ighli di Bari
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Paola Pontrelli
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
| | - Loreto Gesualdo
- Precision and Regenerative Medicine and Ionian Area, Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari Aldo Moro, Bari, Italy
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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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Arif E, Medunjanin D, Solanki A, Zuo X, Su Y, Dang Y, Winkler B, Lerner K, Kamal AI, Palygin O, Cornier MA, Wolf BJ, Hunt KJ, Lipschutz JH. β 2-Adrenergic receptor agonists as a treatment for diabetic kidney disease. Am J Physiol Renal Physiol 2024; 326:F20-F29. [PMID: 37916289 PMCID: PMC11194047 DOI: 10.1152/ajprenal.00254.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/19/2023] [Accepted: 10/25/2023] [Indexed: 11/03/2023] Open
Abstract
We have previously shown that the long-acting β2-adrenergic receptor (β2-AR) agonist formoterol induced recovery from acute kidney injury in mice. To determine whether formoterol protected against diabetic nephropathy, the most common cause of end-stage kidney disease (ESKD), we used a high-fat diet (HFD), a murine type 2 diabetes model, and streptozotocin, a murine type 1 diabetes model. Following formoterol treatment, there was a marked recovery from and reversal of diabetic nephropathy in HFD mice compared with those treated with vehicle alone at the ultrastructural, histological, and functional levels. Similar results were seen after formoterol treatment in mice receiving streptozotocin. To investigate effects in humans, we performed a competing risk regression analysis with death as a competing risk to examine the association between Veterans with chronic kidney disease (CKD) and chronic obstructive pulmonary disease (COPD), who use β2-AR agonists, and Veterans with CKD but no COPD, and progression to ESKD in a large national cohort of Veterans with stage 4 CKD between 2011 and 2013. Veterans were followed until 2016 or death. ESKD was defined as the initiation of dialysis and/or receipt of kidney transplant. We found that COPD was associated with a 25.6% reduction in progression from stage 4 CKD to ESKD compared with no COPD after adjusting for age, diabetes, sex, race-ethnicity, comorbidities, and medication use. Sensitivity analysis showed a 33.2% reduction in ESKD in Veterans with COPD taking long-acting formoterol and a 20.8% reduction in ESKD in Veterans taking other β2-AR agonists compared with those with no COPD. These data indicate that β2-AR agonists, especially formoterol, could be a treatment for diabetic nephropathy and perhaps other forms of CKD.NEW & NOTEWORTHY Diabetic nephropathy is the most common cause of ESKD. Formoterol, a long-acting β2-adrenergic receptor (β2-AR) agonist, reversed diabetic nephropathy in murine models of type 1 and 2 diabetes. In humans, there was an association with protection from progression of CKD in patients with COPD, by means of β2-AR agonist intake, compared with those without COPD. These data indicate that β2-AR agonists, especially formoterol, could be a new treatment for diabetic nephropathy and other forms of CKD.
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Affiliation(s)
- Ehtesham Arif
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Danira Medunjanin
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, South Carolina, United States
- Charleston Health Equity and Rural Outreach Innovation Center, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States
| | - Ashish Solanki
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Xiaofeng Zuo
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Yanhui Su
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Yujing Dang
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Brennan Winkler
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Kasey Lerner
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Ahmed I Kamal
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Oleg Palygin
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Marc-Andre Cornier
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Bethany J Wolf
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, South Carolina, United States
| | - Kelly J Hunt
- Department of Public Health Sciences, Medical University of South Carolina, Charleston, South Carolina, United States
- Charleston Health Equity and Rural Outreach Innovation Center, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States
| | - Joshua H Lipschutz
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina, United States
- Department of Medicine, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina, United States
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Shao Q, Xie X, Geng J, Yang X, Li W, Zhang Y. Frasier Syndrome: A 15-Year-Old Phenotypically Female Adolescent Presenting with Delayed Puberty and Nephropathy. CHILDREN 2023; 10:children10030577. [PMID: 36980135 PMCID: PMC10046944 DOI: 10.3390/children10030577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023]
Abstract
Frasier syndrome (FS) is a rare inherited disorder characterized by gonadal dysgenesis and progressive nephropathy, resulting from mutations in the intron 9 splice donor site of the Wilms tumor 1 (WT1) gene. It is associated with male gonadal dysgenesis (female external genitalia with a 46 XY karyotype), and a high risk of gonadoblastoma during adolescence. Patients with FS present early in childhood with proteinuria that progressively worsens with a high likelihood of end-stage renal disease (ESRD). Herein, we report a 15-year-old female (karyotype 46, XY) patient characterized by delayed puberty and steroid-resistant nephrotic syndrome, in whom whole genome sequencing showed a mutation in intron 9 of the WT1 gene, c.1447 + 4 C>T. This is the first case of FS with delayed puberty as the first complaint with no previous renal symptoms. We consider delayed puberty as an important manifestation of FS and summarize the diagnostic process of delayed puberty in the female phenotype. For clinicians, delayed puberty is a common disorder in pediatrics but requires vigilance for some rare causes. Etiological screening and chromosome karyotype analysis are important for the early diagnosis of FS in patients with delayed puberty.
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Affiliation(s)
- Qing Shao
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Xinglei Xie
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Jia Geng
- Institute of Rare Diseases, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Xiaoling Yang
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Wei Li
- Outpatient Department, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Yuwei Zhang
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Chengdu 610041, China
- Correspondence:
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Sawaf H, Gudura TT, Dorobisz S, Sandy D, Wang X, Bobart SA. Genetic Susceptibility to Chronic Kidney Disease: Links, Risks and Management. Int J Nephrol Renovasc Dis 2023; 16:1-15. [PMID: 36636322 PMCID: PMC9831004 DOI: 10.2147/ijnrd.s363041] [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: 10/05/2022] [Accepted: 12/24/2022] [Indexed: 01/06/2023] Open
Abstract
Chronic kidney disease (CKD) is associated with significant morbidity and mortality worldwide. In recent years, our understanding of genetic causes of CKD has expanded significantly with several renal conditions having been identified. This review discusses the current landscape of genetic kidney disease and their potential treatment options. This review will focus on cystic kidney disease, glomerular disease with genetic associations, congenital anomalies of kidneys and urinary tract (CAKUT), autosomal dominant-tubulointerstitial kidney disease (ADTKD), inherited nephrolithiasis and nephrocalcinosis.
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Affiliation(s)
- Hanny Sawaf
- Department of Kidney Medicine, Cleveland Clinic, Cleveland, OH, USA
| | - Tariku T Gudura
- Department of Kidney Medicine, Cleveland Clinic, Cleveland, OH, USA
| | | | - Dianne Sandy
- Department of Kidney Medicine, Cleveland Clinic Florida, Weston, FL, USA
| | - Xiangling Wang
- Department of Kidney Medicine, Cleveland Clinic, Cleveland, OH, USA
| | - Shane A Bobart
- Department of Kidney Medicine, Cleveland Clinic Florida, Weston, FL, USA,Correspondence: Shane A Bobart, Department of Kidney Medicine, 2950 Cleveland Clinic Blvd, Weston, FL, 33331, USA, Email
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Ye Q, Li Y, Liu H, Mao J, Jiang H. Machine learning models for predicting steroid-resistant of nephrotic syndrome. Front Immunol 2023; 14:1090241. [PMID: 36776850 PMCID: PMC9911108 DOI: 10.3389/fimmu.2023.1090241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 01/09/2023] [Indexed: 01/28/2023] Open
Abstract
Background In the absence of effective measures to predict steroid responsiveness, patients with nonhereditary steroid-resistant nephrotic syndrome (SRNS) have a significantly increased risk of progression to end-stage renal disease. In view of the poor outcomes of SRNS, it is urgent to identify the steroid responsiveness of idiopathic nephrotic syndrome (INS) early. Methods To build a prediction model for SRNS, we collected 91 subjects; 57 of them had steroid-sensitive nephrotic syndrome, and the others had SRNS. For each subject, 87 clinical variables were measured. In general, only a small part of these variables is informative to SRNS. Thus, we proposed a new variable selection framework including a penalized regression approach (named MLR+TLP) to select variables having a linear effect on the SRNS and a nonparametric screening method (MAC) to select variables having a nonlinear marginal (joint) effect on the SRNS. Thereafter, considering the correlation between selected clinical variables, we used a stepwise method to build our final model for predicting SRNS. In addition, a statistical testing procedure is proposed to test the overfitting of the proposed model. Results Twenty-six clinical variables were selected to be informative to SRNS, and an SVM model was built to predict SRNS with a leave-one-out cross-validation (LOO-CV) accuracy of 95.2% (overfitting p value<0.005). To make the model more useful, we incorporate prior medical information into the model and consider the correlation between selected variables. Then, a reduced SVM model including only eight clinical variables (erythrocyte sedimentation rate, urine occult blood, percentage of neutrophils, immunoglobulin A, cholesterol, vinculin autoantibody, aspartate aminotransferase, and prolonged prothrombin time) was built to have a LOO-CV accuracy of 92.8% (overfitting p value<0.005). The validation cohort showed that the reduced model obtained an accuracy of 94.0% (overfitting p value<0.005), with a sensitivity of 90.0% and a specificity of 96.7%. Notably, vinculin autoantibody is the only podocyte autoantibody included in this model. It is linearly related to steroid responsiveness. Finally, our model is freely available as a user-friendly web tool at https://datalinkx.shinyapps.io/srns/. Conclusion The SRNS prediction model constructed in this study comprehensively and objectively evaluates the internal conditions and disease status of INS patients and will provide scientific guidance for selecting treatment methods for children with nonhereditary SRNS.
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Affiliation(s)
- Qing Ye
- Department of Clinical Laboratory, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
| | - Yuzhou Li
- Center for Data Science, Zhejiang University, Hangzhou, China.,School of Mathematical Sciences, Zhejiang University, Hangzhou, China
| | - Huihui Liu
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
| | - Jianhua Mao
- Department of Nephrology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, National Children's Regional Medical Center, Hangzhou, China
| | - Hangjin Jiang
- Center for Data Science, Zhejiang University, Hangzhou, China
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Soraru J, Chakera A, Isbel N, Mallawaarachichi A, Rogers N, Trnka P, Patel C, Mallett A. The evolving role of diagnostic genomics in kidney transplantation. Kidney Int Rep 2022; 7:1758-1771. [PMID: 35967121 PMCID: PMC9366366 DOI: 10.1016/j.ekir.2022.05.019] [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: 04/05/2022] [Revised: 05/11/2022] [Accepted: 05/16/2022] [Indexed: 11/06/2022] Open
Abstract
Monogenic forms of heritable kidney disease account for a significant proportion of chronic kidney disease (CKD) across both pediatric and adult patient populations and up to 11% of patients under 40 years reaching end-stage kidney failure (KF) and awaiting kidney transplant. Diagnostic genomics in the field of nephrology is ever evolving and now plays an important role in assessment and management of kidney transplant recipients and their related donor pairs. Genomic testing can help identify the cause of KF in kidney transplant recipients and assist in prognostication around graft survival and rate of recurrence of primary kidney disease. If a gene variant has been identified in the recipient, at-risk related donors can be assessed for the same and excluded if affected. This paper aims to address the indications for genomic testing in the context for kidney transplantation, the technologies available for testing, the conditions and groups in which testing should be most often considered, and the role for the renal genetics multidisciplinary team in this process.
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Spectrum of NPHS1 and NPHS2 variants in egyptian children with focal segmental glomerular sclerosis: identification of six novel variants and founder effect. Mol Genet Genomics 2022; 297:689-698. [DOI: 10.1007/s00438-022-01877-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 02/20/2022] [Indexed: 01/10/2023]
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Abstract
Nephrotic syndrome (NS) encompasses a variety of disease processes leading to heavy proteinuria and edema. Minimal change disease (MCD) remains the most common primary cause of NS, as well as the most responsive to pharmacologic treatment with often minimal to no chronic kidney disease. Other causes of NS include focal segmental glomerulosclerosis, which follows MCD, and secondary causes, including extrarenal or systemic diseases, infections, and drugs. Although initial diagnosis relies on clinical findings as well as urine and blood chemistries, renal biopsy and genetic testing are important diagnostic tools, especially when considering non-MCD NS. Moreover, biomarkers in urine and serum have become important areas for research in this disease. NS progression and prognosis are variable and depend on etiology, with corticosteroids being the mainstay of treatment. Other alternative therapies found to be successful in inducing and maintaining remission include calcineurin inhibitors and rituximab. Disease course can range from recurrent disease relapse with or without acute kidney injury to end-stage renal disease in some cases. Given the complex pathogenesis of NS, which remains incompletely understood, complications are numerous and diverse and include infections, electrolyte abnormalities, acute kidney injury, and thrombosis. Pediatricians must be aware of the presentation, complications, and overall long-term implications of NS and its treatment.
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Sachdeva S, Khan S, Davalos C, Avanthika C, Jhaveri S, Babu A, Patterson D, Yamani AJ. Management of Steroid-Resistant Nephrotic Syndrome in Children. Cureus 2021; 13:e19363. [PMID: 34925975 PMCID: PMC8654081 DOI: 10.7759/cureus.19363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2021] [Indexed: 11/23/2022] Open
Abstract
Nephrotic syndrome (NS) affects 115-169 children per 100,000, with rates varying by ethnicity and location. Immune dysregulation, systemic circulating substances, or hereditary structural abnormalities of the podocyte are considered to have a role in the etiology of idiopathic NS. Following daily therapy with corticosteroids, more than 85% of children and adolescents (often aged 1 to 12 years) with idiopathic nephrotic syndrome have full proteinuria remission. Patients with steroid-resistant nephrotic syndrome (SRNS) do not demonstrate remission after four weeks of daily prednisolone therapy. The incidence of steroid-resistant nephrotic syndrome in children varies between 35 and 92 percent. A third of SRNS patients have mutations in one of the important podocyte genes. An unidentified circulating factor is most likely to blame for the remaining instances of SRNS. The aim of this article is to explore and review the genetic factors and management of steroid-resistant nephrotic syndrome. An all language literature search was conducted on MEDLINE, COCHRANE, EMBASE, and Google Scholar till September 2021. The following search strings and Medical Subject Headings (MeSH) terms were used: “Steroid resistance”, “nephrotic syndrome”, “nephrosis” and “hypoalbuminemia”. We comprehensively reviewed the literature on the epidemiology, genetics, current treatment protocols, and management of steroid-resistant nephrotic syndrome. We found that for individuals with non-genetic SRNS, calcineurin inhibitors (cyclosporine and tacrolimus) constitute the current mainstay of treatment, with around 70% of patients achieving full or partial remission and an acceptable long-term prognosis. Patients with SRNS who do not react to calcineurin inhibitors or other immunosuppressive medications may have deterioration in kidney function and may develop end-stage renal failure. Nonspecific renal protective medicines, such as angiotensin-converting enzyme inhibitors, angiotensin 2 receptor blockers, and anti-lipid medications, slow the course of the illness. Recurrent focal segmental glomerulosclerosis in the allograft affects around a third of individuals who get a kidney transplant, and it frequently responds to a combination of plasma exchange, rituximab, and increased immunosuppression. Despite the fact that these results show a considerable improvement in outcome, further multicenter controlled studies are required to determine the optimum drugs and regimens to be used.
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Affiliation(s)
| | - Syeda Khan
- Medicine and Surgery, Dow University of Health Sciences, Karachi, PAK
| | | | - Chaithanya Avanthika
- Medicine and Surgery, Karnataka Institute of Medical Sciences, Hubli, IND.,Pediatrics, Karnataka Institute of Medical Sciences, Hubli, IND
| | - Sharan Jhaveri
- Internal Medicine, Smt. NHL Municipal Medical College (MMC), Ahmedabad, IND
| | - Athira Babu
- Pediatrics, Saudi German Hospital, Dubai, ARE
| | | | - Abdullah J Yamani
- Pediatric Medicine, Coast General Teaching and Referral Hospital, Mombasa, KEN
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12
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Primary coenzyme Q10 nephropathy, a potentially treatable form of steroid-resistant nephrotic syndrome. Pediatr Nephrol 2021; 36:3515-3527. [PMID: 33479824 PMCID: PMC8295399 DOI: 10.1007/s00467-020-04914-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/28/2020] [Accepted: 12/31/2020] [Indexed: 12/18/2022]
Abstract
Steroid-resistant nephrotic syndrome (SRNS) is a genetically heterogeneous kidney disease that is the second most frequent cause of kidney failure in the first 2 decades of life. Despite the identification of mutations in more than 39 genes as causing SRNS, and the localization of its pathogenesis to glomerular podocytes, the disease mechanisms of SRNS remain poorly understood and no universally safe and effective therapy exists to treat patients with this condition. Recently, genetic research has identified a subgroup of SRNS patients whose kidney pathology is caused by primary coenzyme Q10 (CoQ10) deficiency due to recessive mutations in genes that encode proteins in the CoQ10 biosynthesis pathway. Clinical and preclinical studies show that primary CoQ10 deficiency may be responsive to treatment with CoQ10 supplements bypassing the biosynthesis defects. Coenzyme Q10 is an essential component of the mitochondrial respiratory chain, where it transports electrons from complexes I and II to complex III. Studies in yeast and mammalian model systems have recently identified the molecular functions of the individual CoQ10 biosynthesis complex proteins, validated these findings, and provided an impetus for developing therapeutic compounds to replenish CoQ10 levels in the tissues/organs and thus prevent the destruction of tissues due to mitochondrial OXPHOS deficiencies. In this review, we will summarize the clinical findings of the kidney pathophysiology of primary CoQ10 deficiencies and discuss recent advances in the development of therapies to counter CoQ10 deficiency in tissues.
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13
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Thakor JM, Parmar G, Mistry KN, Gang S, Rank DN, Joshi CG. Mutational landscape of TRPC6, WT1, LMX1B, APOL1, PTPRO, PMM2, LAMB2 and WT1 genes associated with Steroid resistant nephrotic syndrome. Mol Biol Rep 2021; 48:7193-7201. [PMID: 34546508 DOI: 10.1007/s11033-021-06711-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 09/14/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Nephrotic syndrome appears as a group of symptoms like proteinuria, edema and hyperlipidemia. Identification of monogenic forms revealed the physiology and pathogenesis of the SRNS. METHODS AND RESULTS We performed Illumina panel sequencing of seven genes in 90 Indian patients to determine the role of these genetic mutations in nephrotic syndrome prognosis. Samtool was used for variants calling, and SnpEff and Snpsift did variants annotation. Clinical significance and variant classification were performed by the ClinVar database. In SSNS and SRNS patients, we found 0.78% pathogenic and 3.41% likely pathogenic mutations. Pathogenic mutations were found in LAMB2, LMX1B and WT1 genes, while likely pathogenic mutations were found in (6/13) LAMB2, (2/13) LMX1B, (2/13) TRPC6, (2/13) PTPRO and (1/13) PMM2 genes. Approximately 46% likely pathogenic mutations were contributed to the LAMB2 gene in SSNS and SRNS patients. We also detect 30 VUS (variants of uncertain significance), which were found (17/30) pathogenic and (13/30) likely pathogenic by different prediction tools. CONCLUSIONS Multigene panels were used for genetic screening of heterogeneous disorders like nephrotic syndrome in the Indian population. We found pathogenic, likely pathogenic and certain VUS, which were responsible for the pathogenesis of the disease. Therefore, mutational analysis of SSNS and SRNS is necessary to avoid adverse effects of corticosteroids, modify the intensity of immunosuppressing agents, and prevent the disease's progression.
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Affiliation(s)
- Jinal M Thakor
- Ashok and Rita Patel Institute of Integrated Study and Research in Biotechnology and Allied Sciences, ADIT Campus, New Vallabh Vidyanagar, 388121, Anand, Gujarat, India
| | - Glory Parmar
- Ashok and Rita Patel Institute of Integrated Study and Research in Biotechnology and Allied Sciences, ADIT Campus, New Vallabh Vidyanagar, 388121, Anand, Gujarat, India
| | - Kinnari N Mistry
- Ashok and Rita Patel Institute of Integrated Study and Research in Biotechnology and Allied Sciences, ADIT Campus, New Vallabh Vidyanagar, 388121, Anand, Gujarat, India.
| | - Sishir Gang
- Muljibhai Patel Urological Hospital, Dr. V.V. Desai Road, Nadiad, 387001, Gujarat, India
| | - Dharamshibhai N Rank
- Department of Animal Breeding and Genetics, College of Veterinary Sciences and Animal Husbandry, Anand Agricultural University, Anand, 388110, Gujarat, India
| | - Chaitanya G Joshi
- Department of Animal Biotechnology, College of Veterinary Sciences and Animal Husbandry, Anand Agricultural University, Anand, 388110, Gujarat, India
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14
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Mikó Á, Kaposi A, Schnabel K, Seidl D, Tory K. Identification of incompletely penetrant variants and interallelic interactions in autosomal recessive disorders by a population-genetic approach. Hum Mutat 2021; 42:1473-1487. [PMID: 34405919 DOI: 10.1002/humu.24273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/30/2021] [Accepted: 08/15/2021] [Indexed: 01/11/2023]
Abstract
We aimed to identify incompletely penetrant (IP) variants and interallelic interactions in autosomal recessive disorders by a population-genetic approach. Genotype and clinical data were collected from 9038 patients of European origin with ASL, ATP7B, CAPN3, CFTR, CTNS, DHCR7, GAA, GALNS, GALT, IDUA, MUT, NPHS1, NPHS2, PAH, PKHD1, PMM2, or SLC26A4-related disorders. We calculated the relative allele frequency of each pathogenic variant (n = 1936) to the loss-of-function (LOF) variants of the corresponding gene in the patient ( A C p t V / A C p t L O F ) and the general population ( AC gnomAD V / AC gnomAD LOF ) and estimated the penetrance of each variant by calculating their ratio: ( A C p t V / A C p t L O F ) ( A C g n o m A D V / A C g n o m A D L O F ) (V/LOF ratio). We classified all variants as null or hypomorphic based on the associated clinical phenotype. We found 25 variants, 29% of the frequent 85 variants, to be underrepresented in the patient population (V/LOF ratio <30% with p < 7.22 × 10-5 ), including 22 novel ones in the ASL, CAPN3, CFTR, GAA, GALNS, PAH, and PKHD1 genes. In contrast to the completely penetrant variants (CP), the majority of the IP variants were hypomorphic (IP: 16/18, 88%; CP: 177/933, 19.0%; p = 5.12 × 10-10 ). Among them, only the NPHS2 R229Q variant was subject to interallelic interactions. The proposed algorithm identifies frequent IP variants and estimates their penetrance and interallelic interactions in large patient cohorts.
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Affiliation(s)
- Ágnes Mikó
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.,1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Ambrus Kaposi
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.,Department of Programming Languages and Compilers, Faculty of Informatics, Eötvös Loránd University, Budapest, Hungary
| | - Karolina Schnabel
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.,1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Dániel Seidl
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.,1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Kálmán Tory
- MTA-SE Lendület Nephrogenetic Laboratory, Hungarian Academy of Sciences, Budapest, Hungary.,1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
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15
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Guo HL, Li L, Xu ZY, Jing X, Xia Y, Qiu JC, Ji X, Chen F, Xu J, Zhao F. Steroid-resistant Nephrotic Syndrome in Children: A Mini-review on Genetic Mechanisms, Predictive Biomarkers and Pharmacotherapy Strategies. Curr Pharm Des 2021; 27:319-329. [PMID: 33138756 DOI: 10.2174/1381612826666201102104412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 08/11/2020] [Indexed: 11/22/2022]
Abstract
Steroid-resistant nephrotic syndrome (SRNS) constitutes the second most frequent cause of chronic kidney disease in childhood. The etiology of SRNS remains largely unknown and no standardized treatment exists. Recent advances in genomics have helped to build understanding of the molecular mechanisms and pathogenesis of the disease. The genetic polymorphisms in genes encoding proteins which are involved in the pharmacokinetics and pharmacodynamics of glucocorticoids (GCs) partially account for the different responses between patients with nephrotic syndrome. More importantly, single-gene causation in podocytes-associated proteins was found in approximately 30% of SRNS patients. Some potential biomarkers have been tested for their abilities to discriminate against pediatric patients who are sensitive to GCs treatment and patients who are resistant to the same therapy. This article reviews the recent findings on genetic mechanisms, predictive biomarkers and current therapies for SRNS with the goal to improve the management of children with this syndrome.
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Affiliation(s)
- Hong-Li Guo
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - Ling Li
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Ze-Yue Xu
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Xia Jing
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - Ying Xia
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - Jin-Chun Qiu
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - Xing Ji
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - Feng Chen
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - Jing Xu
- Department of Pharmacy, Children's Hospital of Nanjing Medical University, Nanjing 210008, China
| | - Fei Zhao
- Department of Nephrology, Children's Hospital of Nanjing Medical University, Nanjing, China
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16
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Lucafò M, Granata S, Bonten EJ, McCorkle R, Stocco G, Caletti C, Selvestrel D, Cozzarolo A, Zou C, Cuzzoni E, Pasini A, Montini G, Gambaro G, Decorti G, Evans W, Zaza G. Hypomethylation of NLRP3 gene promoter discriminates glucocorticoid-resistant from glucocorticoid-sensitive idiopathic nephrotic syndrome patients. Clin Transl Sci 2021; 14:964-975. [PMID: 33382913 PMCID: PMC8212736 DOI: 10.1111/cts.12961] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/05/2020] [Accepted: 11/15/2020] [Indexed: 02/06/2023] Open
Abstract
Abstract To assess whether NLRP3 gene promoter methylation was able to discriminate glucocorticoid (GC)‐resistant from GC‐sensitive idiopathic nephrotic syndrome (INS), patients with minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS), we measured the methylation level of NLRP3 promoter in DNA from peripheral blood cells of 10 adult patients with GC‐resistant FSGS already in hemodialysis and 18 patients with GC‐sensitive INS (13 MCD/5 FSGS) and in 21 pediatric patients with INS with MCD/FSGS before starting any treatment. Association of NLRP3 inflammasome with GC resistance was recapitulated in vitro in monocytic cell lines (THP‐1 and U937). In both adults and pediatric patients, NLRP3 promoter methylation was significantly reduced in GC‐resistant compared with GC‐sensitive patients. Indeed, NLRP3 methylation distinguished GC‐resistant and GC‐sensitive patients (area under the receiver operating characteristic curve [AUROC] 86.7% in adults, p = 0.00019, and 73.5% in children, p = 0.00097). NLRP3 knock‐down augmented sensitivity to GCs in THP‐1 cells, whereas NLRP3 inflammasome activation lowered GC receptor concentration, increasing GC resistance in U937 cells. Our results uncovered a new biological mechanism by which patients with INS may acquire GC resistance, that could be used in future as a novel noninvasive diagnostic tool. Study Highlights WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?
☑ Approximately 80% of patients with idiopathic nephrotic syndrome (INS) respond to glucocorticoids, with the remaining 20% being steroid‐resistant.
WHAT QUESTION DID THIS STUDY ADDRESS?
☑ Whether NLRP3 gene promoter methylation was able to discriminate glucocorticoid‐resistant from glucocorticoid (GC)‐sensitive INS.
WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?
☑ In both adults and children, NLRP3 promoter methylation was significantly reduced in leukocytes of patients with GC‐resistant compared with GC‐sensitive INS. NLRP3 inflammasome activation lowered GC receptor concentration and augmented GC resistance, whereas NLRP3 knockdown increased sensitivity to GCs in cell lines representative of monocytes (U937 and THP1).
HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?
☑ Our findings uncovered a new biological mechanism whereby patients with INS may develop resistance to GCs that could be used in the future as a novel noninvasive diagnostic tool.
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Affiliation(s)
- Marianna Lucafò
- Institute for Maternal and Child Health I.R.C.C.S. Burlo Garofolo, Trieste, Italy
| | - Simona Granata
- Renal Unit, Department of Medicine, University Hospital of Verona, Verona, Italy
| | - Erik J Bonten
- Hematological Malignancies Program, Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Robert McCorkle
- Hematological Malignancies Program, Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Gabriele Stocco
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Chiara Caletti
- Renal Unit, Department of Medicine, University Hospital of Verona, Verona, Italy
| | | | | | - Chan Zou
- Hematological Malignancies Program, Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Eva Cuzzoni
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Andrea Pasini
- Nephrology and Dialysis Unit, Department of Pediatrics, Azienda Ospedaliero Universitaria, Policlinico Sant'Orsola-Malpighi, Bologna, Italy
| | - Giovanni Montini
- Pediatric Nephrology, Dialysis and Transplant Unit, Fondazione Ca' Granda IRCCS, Policlinico di Milano, Milano, Italy.,Giuliana and Bernardo Caprotti Chair of Pediatrics, Department of Clinical Sciences and Community Health, University of Milano, Milano, Italy
| | - Giovanni Gambaro
- Renal Unit, Department of Medicine, University Hospital of Verona, Verona, Italy
| | - Giuliana Decorti
- Institute for Maternal and Child Health I.R.C.C.S. Burlo Garofolo, Trieste, Italy.,Giuliana and Bernardo Caprotti Chair of Pediatrics, Department of Clinical Sciences and Community Health, University of Milano, Milano, Italy.,Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - William Evans
- Hematological Malignancies Program, Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Gianluigi Zaza
- Renal Unit, Department of Medicine, University Hospital of Verona, Verona, Italy
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Current Therapies in Nephrotic Syndrome: HDAC inhibitors, an Emerging Therapy for Kidney Diseases. CURRENT RESEARCH IN BIOTECHNOLOGY 2021. [DOI: 10.1016/j.crbiot.2021.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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18
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Structural features and oligomeric nature of human podocin domain. Biochem Biophys Rep 2020; 23:100774. [PMID: 32617419 PMCID: PMC7322680 DOI: 10.1016/j.bbrep.2020.100774] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/31/2020] [Accepted: 06/02/2020] [Indexed: 12/29/2022] Open
Abstract
Podocytes are crucial cells of the glomerular filtration unit and plays a vital role at the interface of the blood-urine barrier. Podocyte slit-diaphragm is a modified tight junction that facilitates size and charge-dependent permselectivity. Several proteins including podocin, nephrin, CD2AP, and TRPC6 form a macromolecular assembly and constitute the slit-diaphragm. Podocin is an integral membrane protein attached to the inner membrane of the podocyte via a short transmembrane region (101–125). The cytosolic N- and C-terminus help podocin to attain a hook-like structure. Podocin shares 44% homology with stomatin family proteins and similar to the stomatin proteins, podocin was shown to associate into higher-order oligomers at the site of slit-diaphragm. However, the stoichiometry of the homo-oligomers and how it partakes in the macromolecular assemblies with other slit-diaphragm proteins remains elusive. Here we investigated the oligomeric propensity of a truncated podocin construct (residues:126–350). We show that the podocin domain majorly homo-oligomerizes into a 16-mer. Circular dichroism and fluorescence spectroscopy suggest that the 16-mer oligomer has considerable secondary structure and moderate tertiary packing. Cloning, expression, and purification of truncated podocin (residues: 126–350). The truncated podocin predominantly associates into 16mer oligomers. The oligomers though possesses secondary structure lacks tight tertiary packing. The oligomeric ensemble has different dissociation temperatures.
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Key Words
- CD, Circular dichroism
- CD2AP, CD-2 associated protein
- GFB, Glomerular filtration barrier
- IDRs, Intrinsically disordered regions
- MALS, multi-angle light scattering
- NEPH, Nephrin-like protein
- NPHS1 & 2, Nephrotic syndrome-type I and type II
- NS, Nephrotic syndrome
- Nephrotic syndrome
- Podocin
- Podocyte
- Proteinuria
- SD, slit-diaphragm
- SEC, Size-exclusion chromatography
- SRNS, steroid-resistant NS
- Slit-diaphragm
- TRPC6, Transient receptor potential cation channel subfamily C member 6
- ZO-1, Zonula occludens-1
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Demir E, Caliskan Y. Variations of type IV collagen-encoding genes in patients with histological diagnosis of focal segmental glomerulosclerosis. Pediatr Nephrol 2020; 35:927-936. [PMID: 31254113 DOI: 10.1007/s00467-019-04282-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/01/2019] [Accepted: 05/31/2019] [Indexed: 01/07/2023]
Abstract
Focal segmental glomerulosclerosis (FSGS), an important cause of end-stage kidney disease (ESKD), covers a spectrum of clinicopathological syndromes sharing a common glomerular lesion, based on an injury of podocytes caused by diverse insults to glomeruli. Although it is well expressed in many reports that the term FSGS is not useful and applicable to a single disease, particularly in genetic studies, FSGS continues to be used as a single clinical diagnosis. Distinguishing genetic forms of FSGS is important for the treatment and overall prognosis because secondary forms of FSGS, produced by rare pathogenic variations in podocyte genes, are not good candidates for immunosuppressive treatment. Over the past decade, several next generation sequencing (NGS) methods have been used to investigate the patients with steroid resistance nephrotic syndrome (SRNS) or FSGS. Pathogenic variants in COL4A3, COL4A4, or COL4A5 genes have been frequently identified in patients with histologic diagnosis of FSGS. The contribution of these mostly heterozygous genetic variations in FSGS pathogenesis and the clinical course of patients with these variations have not been well characterized. This review emphasizes the importance of appropriate approach in selection and diagnosis of cases and interpretation of the genetic data in these studies and suggests a detailed review of existing clinical variant databases using newly available population genetic data.
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Affiliation(s)
- Erol Demir
- Division of Nephrology, Department of Internal Medicine, Istanbul School of Medicine, Istanbul University, Capa, Fatih, 34093, Istanbul, Turkey
| | - Yasar Caliskan
- Division of Nephrology, Department of Internal Medicine, Istanbul School of Medicine, Istanbul University, Capa, Fatih, 34093, Istanbul, Turkey.
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20
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Chamgordani LE, Ebrahimi N, Amirmahani F, Vallian S. CG/CA genotypes represent novel markers in the NPHS2 gene region associated with nephrotic syndrome. J Genet 2020. [DOI: 10.1007/s12041-020-1188-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Hosseiniyan Khatibi SM, Ardalan M, Abediazar S, Zununi Vahed S. The impact of steroids on the injured podocytes in nephrotic syndrome. J Steroid Biochem Mol Biol 2020; 196:105490. [PMID: 31586640 DOI: 10.1016/j.jsbmb.2019.105490] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/03/2019] [Accepted: 09/30/2019] [Indexed: 12/17/2022]
Abstract
Nephrotic syndrome (NS), a common chronic kidney disease, embraces a variety of kidney disorders. Though Glucocorticoids (GCs) are generally used in the treatment of NS, their mechanism of action is poorly understood. A plethora of evidence indicates that podocytes are considered as the main target cells for the therapeutic strategies to prevent NS. GCs regulate the transactivation and transrepression of genes in podocytes that affect their morphological and cytoskeletal features, motility, apoptosis and survival rate. Moreover, they prevent protein leakage through the glomerular barrier membrane by affecting the synthesis, trafficking and posttranslational modifications of slit diaphragms components, podocytes' intercellular junctions. The response to the treatment is variable among different ethnics and populations and resistance to the steroids is detected in almost 50% of adult patients. Not only do pharmacokinetics and pharmacogenetics of steroids play a role in GC resistance but also the genetic variations in one or more podocyte related genes are connected with the steroid resistance in cases with NS. The focus of this review is to explain the underlying cellular and molecular mechanisms of GCs in podocytes. Understanding the mechanisms by which the GCs and GCs receptors in podocytes regulate the gene expression network and crosstalk with other molecular pathways would guarantee an optimum therapeutic benefit of steroid treatment.
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Affiliation(s)
| | | | - Sima Abediazar
- Kidney Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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22
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Basit S, Al-Edressi HM, Sairafi MH, Hashmi JA, Alharby E, Safar R, Ramzan K. Centromere protein I (CENPI) is a candidate gene for X-linked steroid sensitive nephrotic syndrome. J Nephrol 2020; 33:763-769. [PMID: 31912435 DOI: 10.1007/s40620-019-00692-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/21/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Individuals with proteinuria in association with hypoalbuminemia, edema, and hyperlipidemia are considered as having nephrotic syndrome (NS). NS is the most common kidney disease seen in the paediatric age group. NS is usually classified into steroid resistant nephrotic syndrome (SRNS) and steroid sensitive nephrotic syndrome (SSNS). More than 58 genes have been identified as a monogenic cause of SRNS, however, the genetic architecture of childhood SSNS remains poorly understood. METHODS Here in this study, we performed sequencing of 66 NS candidate genes followed by whole genome SNP genotyping and whole exome sequencing in SSNS families with multiple affected individuals. RESULTS NS candidate genes sequencing did not identify any pathogenic variant in the known genes. Homozygosity mapping based on an autosomal recessive model failed to detect any shared loss of heterozygosity region in the genome. An unbiased and hypothesis-free exome data analysis identified a missense variant (c.383G>A; p.Arg128Gln) in the CENPI gene. Sanger sequencing of both parents, unaffected and affected individuals confirmed an X-linked inheritance pattern of the variant (c.383G>A) with SSNS phenotype. The variant (c.383G>A) is very rare and is potentially damaging. CONCLUSION Collectively, these observations suggest that a specific pathogenic link between SSNS development and alteration in CENPI exists. However, human mutations in CENPI causing SSNS have not been reported hitherto. Identification of genetic defects underlying SSNS will help in understanding the precise aetiology of SSNS and improved management of children with NS.
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Affiliation(s)
- Sulman Basit
- Center for Genetics and Inherited Diseases, Taibah University Almadinah Almunawwarah, Medina, 42318, Kingdom of Saudi Arabia.
| | | | - Mona Hamza Sairafi
- Department of Nephrology, Madinah Maternity and Children Hospital, Medina, 42319, Kingdom of Saudi Arabia
| | - Jamil Amjad Hashmi
- Center for Genetics and Inherited Diseases, Taibah University Almadinah Almunawwarah, Medina, 42318, Kingdom of Saudi Arabia
| | - Essa Alharby
- Center for Genetics and Inherited Diseases, Taibah University Almadinah Almunawwarah, Medina, 42318, Kingdom of Saudi Arabia
| | - Ramzia Safar
- Department of Nephrology, Madinah Maternity and Children Hospital, Medina, 42319, Kingdom of Saudi Arabia
| | - Khushnooda Ramzan
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
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23
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Braun DA, Warejko JK, Ashraf S, Tan W, Daga A, Schneider R, Hermle T, Jobst-Schwan T, Widmeier E, Majmundar AJ, Nakayama M, Schapiro D, Rao J, Schmidt JM, Hoogstraten CA, Hugo H, Bakkaloglu SA, Kari JA, El Desoky S, Daouk G, Mane S, Lifton RP, Shril S, Hildebrandt F. Genetic variants in the LAMA5 gene in pediatric nephrotic syndrome. Nephrol Dial Transplant 2019. [PMID: 29534211 DOI: 10.1093/ndt/gfy028] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Nephrotic syndrome (NS), a chronic kidney disease, is characterized by significant loss of protein in the urine causing hypoalbuminemia and edema. In general, ∼15% of childhood-onset cases do not respond to steroid therapy and are classified as steroid-resistant NS (SRNS). In ∼30% of cases with SRNS, a causative mutation can be detected in one of 44 monogenic SRNS genes. The gene LAMA5 encodes laminin-α5, an essential component of the glomerular basement membrane. Mice with a hypomorphic mutation in the orthologous gene Lama5 develop proteinuria and hematuria. METHODS To identify additional monogenic causes of NS, we performed whole exome sequencing in 300 families with pediatric NS. In consanguineous families we applied homozygosity mapping to identify genomic candidate loci for the underlying recessive mutation. RESULTS In three families, in whom mutations in known NS genes were excluded, but in whom a recessive, monogenic cause of NS was strongly suspected based on pedigree information, we identified homozygous variants of unknown significance (VUS) in the gene LAMA5. While all affected individuals had nonsyndromic NS with an early onset of disease, their clinical outcome and response to immunosuppressive therapy differed notably. CONCLUSION We here identify recessive VUS in the gene LAMA5 in patients with partially treatment-responsive NS. More data will be needed to determine the impact of these VUS in disease management. However, familial occurrence of disease, data from genetic mapping and a mouse model that recapitulates the NS phenotypes suggest that these genetic variants may be inherited factors that contribute to the development of NS in pediatric patients.
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Affiliation(s)
- Daniela A Braun
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jillian K Warejko
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shazia Ashraf
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Weizhen Tan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ankana Daga
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ronen Schneider
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tobias Hermle
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tilman Jobst-Schwan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Eugen Widmeier
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Amar J Majmundar
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Makiko Nakayama
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - David Schapiro
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jia Rao
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | - Hannah Hugo
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Jameela A Kari
- Pediatric Nephrology Center of Excellence and Pediatrics Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Sherif El Desoky
- Pediatric Nephrology Center of Excellence and Pediatrics Department, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ghaleb Daouk
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
| | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA.,Laboratory of Human Genetics and Genomics, Rockefeller University, New York, NY, USA
| | - Shirlee Shril
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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24
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Govender MA, Fabian J, Gottlich E, Levy C, Moonsamy G, Maher H, Winkler CA, Ramsay M. The podocin V260E mutation predicts steroid resistant nephrotic syndrome in black South African children with focal segmental glomerulosclerosis. Commun Biol 2019; 2:416. [PMID: 31754646 PMCID: PMC6858321 DOI: 10.1038/s42003-019-0658-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 10/22/2019] [Indexed: 01/17/2023] Open
Abstract
In black African children with focal segmental glomerulosclerosis (FSGS) there are high rates of steroid resistance. The aim was to determine genetic associations with apolipoprotein L1 (APOL1) renal risk variants and podocin (NPHS2) variants in 30 unrelated black South African children with FSGS. Three APOL1 variants were genotyped and the exons of the NPHS2 gene sequenced in the cases and controls. APOL1 risk alleles show a modest association with steroid sensitive nephrotic syndrome (SSNS) and steroid resistant nephrotic syndrome (SRNS). The NPHS2 V260E variant was present in SRNS cases (V/V = 5; V/E = 4; E/E = 11), and was absent in SSNS cases. Haplotype analysis suggests a single mutation origin for V260E and it was associated with a decline in kidney function over a 60-month period (p = 0.026). The V260E variant is a good predictor of autosomal recessive SRNS in black South African children and could provide useful information in a clinical setting.
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Affiliation(s)
- Melanie A. Govender
- Sydney Brenner Institute for Molecular Bioscience and Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - June Fabian
- Wits Donald Gordon Medical Centre, University of the Witwatersrand, Johannesburg, South Africa
- Division of Nephrology, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Errol Gottlich
- Wits Donald Gordon Medical Centre, University of the Witwatersrand, Johannesburg, South Africa
- Department of Paediatrics, University of Pretoria, Pretoria, South Africa
| | - Cecil Levy
- Nelson Mandela Children’s Hospital, Division of Nephrology, Department of Paediatrics, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Glenda Moonsamy
- Charlotte Maxeke Johannesburg Academic Hospital, Division of Nephrology, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Heather Maher
- Wits Donald Gordon Medical Centre, University of the Witwatersrand, Johannesburg, South Africa
| | - Cheryl A. Winkler
- Basic Research Laboratory, Center for Cancer Research, National Cancer Institute, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, MD USA
| | - Michèle Ramsay
- Sydney Brenner Institute for Molecular Bioscience and Division of Human Genetics, National Health Laboratory Service and School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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25
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Wu X, Wang W, Liu Y, Chen W, Zhao L. A steroid-resistant nephrotic syndrome in an infant resulting from a consanguineous marriage with COQ2 and ARSB gene mutations: a case report. BMC MEDICAL GENETICS 2019; 20:165. [PMID: 31660881 PMCID: PMC6816174 DOI: 10.1186/s12881-019-0898-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 09/25/2019] [Indexed: 12/03/2022]
Abstract
Background Treatment of steroid-resistant nephrotic syndrome (SRNS) remains a challenge for paediatricians. SRNS accounts for 10~20% of childhood cases of nephrotic syndrome (NS). Individuals with SRNS overwhelmingly progress to chronic kidney disease (CKD) and end-stage kidney disease (ESRD). Genetic research is of great significance for diagnosis and treatment. More than 39 recessive or dominant genes have been found to cause human SRNS, including COQ2. COQ2 gene mutations not only cause primary coenzyme Q10 deficiency but also cause SRNS without extrarenal manifestations. The concept of COQ2 nephropathy has been proposed for a long time. Mutations in the COQ2 gene have rarely been reported. Worldwide, only 5 cases involving 4 families have been reported. Case presentation We present the case of a 6-month-old girl with steroid-resistant glomerulopathy due to a COQ2 defect with no additional systemic symptoms. The patient was identified as a homozygote for the c.832 T > C (p. Cys278Arg) missense mutation and a single base homozygous mutation in ARSB gene in c.1213 + 1G > A. The father and mother were heterozygous mutation carriers in both COQ2 and ARSB, and her healthy sister was only a heterozygous mutation carrier in COQ2. In this case, hormone therapy was ineffective, and progressive deterioration of renal function occurred within 1 week after onset, leading to acute renal failure and eventual death. Conclusions We reported a consanguinity married family which had COQ2 and ARSB dual mutant. Kidney diseases caused by COQ2 gene mutations can manifest as SRNS, with poor prognosis. The C. 832 T > c (p.csc 278arg) is a new mutation site. Genetic assessment for children with steroid-resistant nephrotic syndrome, especially in infancy, is very important. Families with a clear family history should receive genetic counselling and prenatal examinations, and children without a family phenotype should also receive genetic screening as early as possible.
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Affiliation(s)
- Xia Wu
- Department of Nephrology, Tianjin Children's Hospital, 238 Longyan Road, Beichen District, Tianjin, China
| | - Wenhong Wang
- Department of Nephrology, Tianjin Children's Hospital, 238 Longyan Road, Beichen District, Tianjin, China.
| | - Yan Liu
- Department of Nephrology, Tianjin Children's Hospital, 238 Longyan Road, Beichen District, Tianjin, China
| | - Wenyu Chen
- Department of Nephrology, Tianjin Children's Hospital, 238 Longyan Road, Beichen District, Tianjin, China
| | - Linsheng Zhao
- Department of Pathology, Tianjin Children's Hospital, 238 Longyan Road, Beichen District, Tianjin, China
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26
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Guaragna MS, de Brito Lutaif ACG, de Souza ML, Maciel-Guerra AT, Belangero VMS, Guerra-Júnior G, de Mello MP. Promises and pitfalls of whole-exome sequencing exemplified by a nephrotic syndrome family. Mol Genet Genomics 2019; 295:135-142. [PMID: 31520189 DOI: 10.1007/s00438-019-01609-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023]
Abstract
High-throughput techniques such as whole-exome sequencing (WES) show promise for the identification of candidate genes that underlie Mendelian diseases such as nephrotic syndrome (NS). These techniques have enabled the identification of a proportion of the approximately 54 genes associated with NS. However, the main pitfall of using WES in clinical and research practice is the identification of multiple variants, which hampers interpretation during downstream analysis. One useful strategy is to evaluate the co-inheritance of rare variants in affected family members. Here, we performed WES of a patient with steroid-resistant NS (SRNS) and intermittent microhematuria. Currently, 15 years after kidney transplantation, this patient presents normal kidney function. The patient was found to be homozygous for a rare MYO1E stop-gain variant, and was heterozygous for rare variants in NS-associated genes, COL4A4, KANK1, LAMB2, ANLN, E2F3, and APOL1. We evaluated the presence or absence of these variants in both parents and 11 siblings, three of whom exhibited a milder phenotype of the kidney disease. Analysis of variant segregation in the family, indicated the MYO1E stop-gain variant as the putative causal variant underlying the kidney disease in the patient and two of her affected sisters. Two secondary variants in COL4A4-identified in some other affected family members-require further functional studies to determine whether they play a role in the development of microhematuria in affected family members. Our data illustrate the difficulties in distinguishing the causal pathogenic variants from incidental findings after WES-based variant analysis, especially in heterogenous genetic conditions, such as NS.
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Affiliation(s)
- Mara Sanches Guaragna
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil.
| | - Anna Cristina Gervásio de Brito Lutaif
- Integrated Center of Pediatric Nephrology (CIN), Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas, UNICAMP, Campinas, Brazil
| | - Marcela Lopes de Souza
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil
| | | | - Vera Maria Santoro Belangero
- Integrated Center of Pediatric Nephrology (CIN), Department of Pediatrics, School of Medical Sciences (FCM), State University of Campinas, UNICAMP, Campinas, Brazil.,Department of Pediatrics, School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil
| | - Gil Guerra-Júnior
- Department of Pediatrics, School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil.,Growth and Development Laboratory, Center for Investigation in Pediatrics (CIPED), School of Medical Sciences (FCM), UNICAMP, Campinas, SP, Brazil
| | - Maricilda Palandi de Mello
- Laboratory of Human Molecular Genetics, Center for Molecular Biology and Genetic Engineering (CBMEG), State University of Campinas, UNICAMP, Caixa Postal 6010, 13083-875, Campinas, SP, Brazil
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27
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Arif E, Solanki AK, Srivastava P, Rahman B, Fitzgibbon WR, Deng P, Budisavljevic MN, Baicu CF, Zile MR, Megyesi J, Janech MG, Kwon SH, Collier J, Schnellmann RG, Nihalani D. Mitochondrial biogenesis induced by the β2-adrenergic receptor agonist formoterol accelerates podocyte recovery from glomerular injury. Kidney Int 2019; 96:656-673. [PMID: 31262488 PMCID: PMC6708766 DOI: 10.1016/j.kint.2019.03.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 03/07/2019] [Accepted: 03/28/2019] [Indexed: 01/14/2023]
Abstract
Podocytes have limited ability to recover from injury. Here, we demonstrate that increased mitochondrial biogenesis, to meet the metabolic and energy demand of a cell, accelerates podocyte recovery from injury. Analysis of events induced during podocyte injury and recovery showed marked upregulation of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a transcriptional co-activator of mitochondrial biogenesis, and key components of the mitochondrial electron transport chain. To evaluate our hypothesis that increasing mitochondrial biogenesis enhanced podocyte recovery from injury, we treated injured podocytes with formoterol, a potent, specific, and long-acting β2-adrenergic receptor agonist that induces mitochondrial biogenesis in vitro and in vivo. Formoterol increased mitochondrial biogenesis and restored mitochondrial morphology and the injury-induced changes to the organization of the actin cytoskeleton in podocytes. Importantly, β2-adrenergic receptors were found to be present on podocyte membranes. Their knockdown attenuated formoterol-induced mitochondrial biogenesis. To determine the potential clinical relevance of these findings, mouse models of acute nephrotoxic serum nephritis and chronic (Adriamycin [doxorubicin]) glomerulopathy were used. Mice were treated with formoterol post-injury when glomerular dysfunction was established. Strikingly, formoterol accelerated the recovery of glomerular function by reducing proteinuria and ameliorating kidney pathology. Furthermore, formoterol treatment reduced cellular apoptosis and increased the expression of the mitochondrial biogenesis marker PGC-1α and multiple electron transport chain proteins. Thus, our results support β2-adrenergic receptors as novel therapeutic targets and formoterol as a therapeutic compound for treating podocytopathies.
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Affiliation(s)
- Ehtesham Arif
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Ashish K Solanki
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Pankaj Srivastava
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Bushra Rahman
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Wayne R Fitzgibbon
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Peifeng Deng
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Milos N Budisavljevic
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Catalin F Baicu
- Division of Cardiology, Medical University of South Carolina, Charleston, South Carolina, USA; Ralph H. Johnson VA Medical Center, Charleston, South Carolina, USA
| | - Michael R Zile
- Division of Cardiology, Medical University of South Carolina, Charleston, South Carolina, USA; Ralph H. Johnson VA Medical Center, Charleston, South Carolina, USA
| | - Judit Megyesi
- John C McClelland VA Hospital, Little Rock, Arkansas, USA
| | | | - Sang-Ho Kwon
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia, USA
| | - Justin Collier
- Department of Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Rick G Schnellmann
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona, USA; Southern Arizona VA Health Care System, Tucson, Arizona, USA.
| | - Deepak Nihalani
- Department of Medicine, Nephrology Division, Medical University of South Carolina, Charleston, South Carolina, USA.
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28
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Donnan MD, Scott RP, Onay T, Tarjus A, Onay UV, Quaggin SE. Genetic Deletion of Emp2 Does Not Cause Proteinuric Kidney Disease in Mice. Front Med (Lausanne) 2019; 6:189. [PMID: 31508419 PMCID: PMC6718710 DOI: 10.3389/fmed.2019.00189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 08/09/2019] [Indexed: 12/15/2022] Open
Abstract
Nephrotic syndrome is one of the most common glomerular diseases in children and can be classified on the basis of steroid responsiveness. While multiple genetic causes have been discovered for steroid resistant nephrotic syndrome, the genetics of steroid sensitive nephrotic syndrome remains elusive. Mutations in Epithelial Membrane Protein 2 (EMP2), a member of the GAS3/PMP22 tetraspan family of proteins, were recently implicated as putative monogenic cause of steroid sensitive nephrotic syndrome. We investigated this hypothesis by developing Emp2 reporter and knockout mouse models. In lacZ reporter mice (engineered to drive expression of the enzyme β-galactosidase under the control of the endogenous murine Emp2 promoter), Emp2 promoter activity was not observed in podocytes but was particularly prominent in medium- and large-caliber arterial vessels in the kidney and other tissues where it localizes specifically in vascular smooth muscle cells (vSMCs) but not in the endothelium. Strong Emp2 expression was also found in non-vascular smooth muscle cells found in other organs like the stomach, bladder, and uterus. Global and podocyte-specific Emp2 knockout mice were viable and did not develop nephrotic syndrome showing no evidence of abnormal glomerular histology or ultrastructure. Altogether, our results do not support that loss of function of EMP2 represent a monogenic cause of proteinuric kidney disease. However, the expression pattern of Emp2 indicates that it may be relevant in smooth muscle function in various organs and tissues including the vasculature.
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Affiliation(s)
- Michael D Donnan
- Division of Nephrology and Hypertension, Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Rizaldy P Scott
- Division of Nephrology and Hypertension, Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Tuncer Onay
- Division of Nephrology and Hypertension, Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Antoine Tarjus
- Division of Nephrology and Hypertension, Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Ummiye Venus Onay
- Division of Nephrology and Hypertension, Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Susan E Quaggin
- Division of Nephrology and Hypertension, Feinberg Cardiovascular and Renal Research Institute, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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29
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Gribouval O, Boyer O, Hummel A, Dantal J, Martinez F, Sberro-Soussan R, Etienne I, Chauveau D, Delahousse M, Lionet A, Allard J, Pouteil Noble C, Tête MJ, Heidet L, Antignac C, Servais A. Identification of genetic causes for sporadic steroid-resistant nephrotic syndrome in adults. Kidney Int 2019; 94:1013-1022. [PMID: 30348286 DOI: 10.1016/j.kint.2018.07.024] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/18/2018] [Accepted: 07/12/2018] [Indexed: 01/15/2023]
Abstract
Monogenic forms of Steroid-Resistant Nephrotic Syndrome (SRNS) have been widely characterized, but genetic screening paradigms preferentially address congenital, infantile onset, and familial cases. Our aim was to characterize the distribution of disease-causing gene mutations in adults with sporadic SRNS or focal segmental glomerulosclerosis (FSGS). We selected adult patients with non-syndromic, biopsy-proven FSGS or SRNS in the absence of known family history. Strict clinical criteria included lack of response to glucocorticoids and cyclosporine, and no recurrence after kidney transplantation. Mutations in SRNS genes were detected using a targeted gene panel. Sixteen of 135 tested participants (11.8%) carried pathogenic mutations in monogenic SRNS genes, and 14 others (10.4%) carried two APOL1 high-risk alleles. Autosomal recessive disease was diagnosed in 5 participants, autosomal dominant disease in 9, and X-linked disease in 2. Four participants carried a de novo heterozygous mutation. Among the 16 participants with identified mutations in monogenic SNRS genes, 7 (43.7%) had type IV collagen mutations. Mutations in monogenic SNRS genes were identified primarily in participants with proteinuria onset before 25 years of age, while the age at disease onset was variable in those with APOL1 high-risk genotype. Mean age at diagnosis was lower and renal survival was worse in participants with identified mutations in SNRS genes than in those without mutations. We found a significant rate of pathogenic mutations in adults with SRNS, with Type IV collagen mutations being the most frequent. These findings may have immediate impact on clinical practice.
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Affiliation(s)
- Olivier Gribouval
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Olivia Boyer
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Pediatric Nephrology, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | - Aurélie Hummel
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Adult Nephrology & Transplantation, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | | | - Frank Martinez
- Adult Nephrology & Transplantation, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | - Rebecca Sberro-Soussan
- Adult Nephrology & Transplantation, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France
| | - Isabelle Etienne
- Nephrology Department, Hôpital de Bois-Guillaume, CHU Rouen, Rouen, France
| | - Dominique Chauveau
- Department of Nephrology and Organ Transplantation, CHU Rangueil, Toulouse, France
| | | | - Arnaud Lionet
- Nephrology Department, Hôpital Huriez, CHU Lille, Lille, France
| | | | - Claire Pouteil Noble
- Nephrology-Transplantation Department, Hôpital Edouard Herriot, Lyon I University, Lyon, France
| | - Marie-Josèphe Tête
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Laurence Heidet
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Pediatric Nephrology, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France; Genetic Department, Necker Hospital, APHP, Paris, France
| | - Corinne Antignac
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Genetic Department, Necker Hospital, APHP, Paris, France.
| | - Aude Servais
- Inserm U1163, Imagine Institute, Paris Descartes University, Paris, France; Adult Nephrology & Transplantation, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Necker Hospital, Paris, France.
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30
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Mulukala Narasimha SK, Kar PP, Vadrevu R, Pasupulati AK. Intrinsically disordered regions mediate macromolecular assembly of the Slit diaphragm proteins associated with Nephrotic syndrome. MOLECULAR SIMULATION 2019. [DOI: 10.1080/08927022.2019.1570508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
| | - Prajna Parimita Kar
- Laboratory of Molecular Interactions, National Institute of Animal Biotechnology, Hyderabad, India
| | - Ramakrishna Vadrevu
- Department of Biological Sciences, BITS-Pilani, Hyderabad Campus, Hyderabad, India
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31
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Jobst-Schwan T, Hoogstraten CA, Kolvenbach CM, Schmidt JM, Kolb A, Eddy K, Schneider R, Ashraf S, Widmeier E, Majmundar AJ, Hildebrandt F. Corticosteroid treatment exacerbates nephrotic syndrome in a zebrafish model of magi2a knockout. Kidney Int 2019; 95:1079-1090. [PMID: 31010479 DOI: 10.1016/j.kint.2018.12.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/21/2018] [Accepted: 12/13/2018] [Indexed: 01/31/2023]
Abstract
Recently, recessive mutations of MAGI2 were identified as a cause of steroid-resistant nephrotic syndrome (SRNS) in humans and mice. To further delineate the pathogenesis of MAGI2 loss of function, we generated stable knockout lines for the two zebrafish orthologues magi2a and magi2b by CRISPR/Cas9. We also developed a novel assay for the direct detection of proteinuria in zebrafish independent of transgenic background. Whereas knockout of magi2b did not yield a nephrotic syndrome phenotype, magi2a-/- larvae developed ascites, periorbital edema, and proteinuria, as indicated by increased excretion of low molecular weight protein. Electron microscopy demonstrated extensive podocyte foot process effacement. As in human SRNS, we observed genotype/phenotype correlation, with edema onset occurring earlier in zebrafish with truncating alleles (5-6 days post fertilization) versus hypomorphic alleles (19-20 days post fertilization). Paradoxically, corticosteroid treatment exacerbated the phenotype, with earlier onset of edema. In contrast, treatment with cyclosporine A or tacrolimus had no significant effect. Although RhoA signaling has been implicated as a downstream mediator of MAGI2 activity, targeting of the RhoA pathway did not modify the nephrotic syndrome phenotype. In the first CRISPR/Cas9 zebrafish knockout model of SRNS, we found that corticosteroids may have a paradoxical effect in the setting of specific genetic mutations.
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Affiliation(s)
- Tilman Jobst-Schwan
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Charlotte A Hoogstraten
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Caroline M Kolvenbach
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Johanna Magdalena Schmidt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Amy Kolb
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Kaitlyn Eddy
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Ronen Schneider
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Shazia Ashraf
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Eugen Widmeier
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Amar J Majmundar
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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Widmeier E, Airik M, Hugo H, Schapiro D, Wedel J, Ghosh CC, Nakayama M, Schneider R, Awad AM, Nag A, Cho J, Schueler M, Clarke CF, Airik R, Hildebrandt F. Treatment with 2,4-Dihydroxybenzoic Acid Prevents FSGS Progression and Renal Fibrosis in Podocyte-Specific Coq6 Knockout Mice. J Am Soc Nephrol 2019; 30:393-405. [PMID: 30737270 PMCID: PMC6405149 DOI: 10.1681/asn.2018060625] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 12/29/2018] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Although studies have identified >55 genes as causing steroid-resistant nephrotic syndrome (SRNS) and localized its pathogenesis to glomerular podocytes, the disease mechanisms of SRNS remain largely enigmatic. We recently reported that individuals with mutations in COQ6, a coenzyme Q (also called CoQ10, CoQ, or ubiquinone) biosynthesis pathway enzyme, develop SRNS with sensorineural deafness, and demonstrated the beneficial effect of CoQ for maintenace of kidney function. METHODS To study COQ6 function in podocytes, we generated a podocyte-specific Coq6 knockout mouse (Coq6podKO ) model and a transient siRNA-based COQ6 knockdown in a human podocyte cell line. Mice were monitored for development of proteinuria and assessed for development of glomerular sclerosis. Using a podocyte migration assay, we compared motility in COQ6 knockdown podocytes and control podocytes. We also randomly assigned 5-month-old Coq6podKO mice and controls to receive no treatment or 2,4-dihydroxybenzoic acid (2,4-diHB), an analog of a CoQ precursor molecule that is classified as a food additive by health authorities in Europe and the United States. RESULTS Abrogation of Coq6 in mouse podocytes caused FSGS and proteinuria (>46-fold increases in albuminuria). In vitro studies revealed an impaired podocyte migration rate in COQ6 knockdown human podocytes. Treating Coq6podKO mice or cells with 2,4-diHB prevented renal dysfunction and reversed podocyte migration rate impairment. Survival of Coq6podKO mice given 2,4diHB was comparable to that of control mice and significantly higher than that of untreated Coq6podKO mice, half of which died by 10 months of age. CONCLUSIONS These findings reveal a potential novel treatment strategy for those cases of human nephrotic syndrome that are caused by a primary dysfunction in the CoQ10 biosynthesis pathway.
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Affiliation(s)
- Eugen Widmeier
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts;,Department of Medicine IV, Medical Center–University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Merlin Airik
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Hannah Hugo
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - David Schapiro
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Johannes Wedel
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Chandra C. Ghosh
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Makiko Nakayama
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ronen Schneider
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Agape M. Awad
- Department of Chemistry and Biochemistry and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California
| | - Anish Nag
- Department of Chemistry and Biochemistry and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California
| | - Jang Cho
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Markus Schueler
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Catherine F. Clarke
- Department of Chemistry and Biochemistry and Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California
| | - Rannar Airik
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Friedhelm Hildebrandt
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
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Genetic testing in steroid-resistant nephrotic syndrome: why, who, when and how? Pediatr Nephrol 2019; 34:195-210. [PMID: 29181713 PMCID: PMC6311200 DOI: 10.1007/s00467-017-3838-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 10/24/2017] [Accepted: 10/25/2017] [Indexed: 12/23/2022]
Abstract
Steroid-resistant nephrotic syndrome (SRNS) is a common cause of chronic kidney disease in childhood and has a significant risk of rapid progression to end-stage renal disease. The identification of over 50 monogenic causes of SRNS has revealed dysfunction in podocyte-associated proteins in the pathogenesis of proteinuria, highlighting their essential role in glomerular function. Recent technological advances in high-throughput sequencing have enabled indication-driven genetic panel testing for patients with SRNS. The availability of genetic testing, combined with the significant phenotypic variability of monogenic SRNS, poses unique challenges for clinicians when directing genetic testing. This highlights the need for clear clinical guidelines that provide a systematic approach for mutational screening in SRNS. The likelihood of identifying a causative mutation is inversely related to age at disease onset and is increased with a positive family history or the presence of extra-renal manifestations. An unequivocal molecular diagnosis could allow for a personalised treatment approach with weaning of immunosuppressive therapy, avoidance of renal biopsy and provision of accurate, well-informed genetic counselling. Identification of novel causative mutations will continue to unravel the pathogenic mechanisms of glomerular disease and provide new insights into podocyte biology and glomerular function.
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Association of Exposure to Fine-Particulate Air Pollution and Acidic Gases with Incidence of Nephrotic Syndrome. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15122860. [PMID: 30558173 PMCID: PMC6313436 DOI: 10.3390/ijerph15122860] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/29/2018] [Accepted: 12/12/2018] [Indexed: 01/15/2023]
Abstract
Background: Air pollution has been associated with autoimmune diseases. Nephrotic syndrome is a clinical manifestation of immune-mediated glomerulopathy. However, the association between nephrotic syndrome and air pollution constituents remains unknown. We conducted this nationwide retrospective study to investigate the association between PM2.5 and nephrotic syndrome. Methods: We used the Longitudinal Health Insurance Database (LHID) and the Taiwan Air Quality-Monitoring Database (TAQMD). We combined and stratified the LHID and the TAQMD data by residential areas of insurants linked to nearby air quality-monitoring stations. Air pollutant concentrations were grouped into four levels based on quartile. Univariable and multivariable Cox proportional hazard regression models were applied. Findings: Relative to Q1-level SO₂, subjects exposed to the Q4 level were associated with a 2.00-fold higher risk of nephrotic syndrome (adjusted HR = 2.00, 95% CI = 1.66⁻2.41). In NOx, relative to Q1 NOx concentrations, the adjusted HRs of nephrotic syndrome risk were 1.53 (95% CI = 1.23⁻1.91), 1.30 (95% CI = 1.03⁻1.65), and 2.08 (95% CI = 1.69⁻2.56) for Q2, Q3, and Q4 levels, respectively. The results revealed an increasing trend for nephrotic syndrome risk correlating with increasing levels of NO, NO₂, and PM2.5 concentrations. Interpretation: High concentrations of PM2.5, NO, NO₂, and SO₂ are associated with increased risk of nephrotic syndrome.
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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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Zhang H, Su B, Liu X, Xiao H, Ding J, Yao Y. Mutations in TTC21B cause different phenotypes in two childhood cases in China. Nephrology (Carlton) 2018; 23:371-376. [PMID: 28124483 DOI: 10.1111/nep.13008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 01/17/2017] [Accepted: 01/22/2017] [Indexed: 12/22/2022]
Abstract
AIM The TTC21B gene is now known as causative of nephronophthisis-related ciliopathies (NPHP-RC). We reported two Chinese paediatric cases with end-stage renal disease and other phenotypes caused by the TTC21B gene mutations. METHODS The clinical features of Chinese paediatric cases with NPHP-RC were summarized. Mutation analysis of the TTC21B gene was performed using next-generation sequencing. RESULTS The two cases both had nephrotic proteinuria, renal failure, hypertension and abnormal liver function (or hepatic fibrosis). One case also presented situs inversus and short phalanges. They developed end-stage renal disease (ESRD) at 1 year old and 8 years old, respectively, when renal pathology both showed focal segmental glomerular sclerosis (FSGS) with tubulointerstitial lesions including interstitial fibrosis and atrophic tubules. Three novel disease-causing TTC21B mutations were identified. One case carried homozygous mutation c.2211 + 3A > G, while the other case carried compound heterozygous mutations c.1552 T > C (p.C518R) and c.1456dupA (p.R486KfsX22). CONCLUSION Mutations in TTC21B cause a range of ciliopathy phenotypes in humans. We identified 3 novel TTC21B mutations in two Chinese paediatric cases that both presented end-stage renal disease and other different features. This is the first TTC21B mutations ever reported in China.
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Affiliation(s)
- Hongwen Zhang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Baige Su
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Xiaoyu Liu
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Huijie Xiao
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Jie Ding
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Yong Yao
- Department of Pediatric, Peking University First Hospital, Beijing, China
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A kidney-disease gene panel allows a comprehensive genetic diagnosis of cystic and glomerular inherited kidney diseases. Kidney Int 2018; 94:363-371. [DOI: 10.1016/j.kint.2018.02.027] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 02/09/2018] [Accepted: 02/15/2018] [Indexed: 12/14/2022]
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Jin YY, Feng BY, Mao JH. The status quo and challenges of genetic diagnosis in children with steroid-resistant nephrotic syndrome. World J Pediatr 2018; 14:105-109. [PMID: 29644498 DOI: 10.1007/s12519-018-0156-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 03/28/2018] [Indexed: 01/12/2023]
Affiliation(s)
- Yan-Yan Jin
- Department of Nephrology, Children's Hospital, Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, China
| | - Bing-Yu Feng
- Department of Nephrology, Children's Hospital, Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, China.,Department of Paediatrics, The First People's Hospital of Huzhou, Huzhou, 313000, China
| | - Jian-Hua Mao
- Department of Nephrology, Children's Hospital, Zhejiang University School of Medicine, #57 Zhugan Lane, Hangzhou, 310003, China.
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Cil O, Perwad F. Monogenic Causes of Proteinuria in Children. Front Med (Lausanne) 2018; 5:55. [PMID: 29594119 PMCID: PMC5858124 DOI: 10.3389/fmed.2018.00055] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/15/2018] [Indexed: 01/02/2023] Open
Abstract
Glomerular disease is a common cause for proteinuria and chronic kidney disease leading to end-stage renal disease requiring dialysis or kidney transplantation in children. Nephrotic syndrome in children is diagnosed by the presence of a triad of proteinuria, hypoalbuminemia, and edema. Minimal change disease is the most common histopathological finding in children and adolescents with nephrotic syndrome. Focal segmental sclerosis is also found in children and is the most common pathological finding in patients with monogenic causes of nephrotic syndrome. Current classification system for nephrotic syndrome is based on response to steroid therapy as a majority of patients develop steroid sensitive nephrotic syndrome regardless of histopathological diagnosis or the presence of genetic mutations. Recent studies investigating the genetics of nephrotic syndrome have shed light on the pathophysiology and mechanisms of proteinuria in nephrotic syndrome. Gene mutations have been identified in several subcellular compartments of the glomerular podocyte and play a critical role in mitochondrial function, actin cytoskeleton dynamics, cell-matrix interactions, slit diaphragm, and podocyte integrity. A subset of genetic mutations are known to cause nephrotic syndrome that is responsive to immunosuppressive therapy but clinical data are limited with respect to renal prognosis and disease progression in a majority of patients. To date, more than 50 genes have been identified as causative factors in nephrotic syndrome in children and adults. As genetic testing becomes more prevalent and affordable, we expect rapid advances in our understanding of mechanisms of proteinuria and genetic diagnosis will help direct future therapy for individual patients.
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Affiliation(s)
- Onur Cil
- Department of Pediatrics, Division of Nephrology, University of California San Francisco, San Francisco, CA, United States
| | - Farzana Perwad
- Department of Pediatrics, Division of Nephrology, University of California San Francisco, San Francisco, CA, United States
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Braunisch MC, Büttner-Herold M, Günthner R, Satanovskij R, Riedhammer KM, Herr PM, Klein HG, Wahl D, Küchle C, Renders L, Heemann U, Schmaderer C, Hoefele J. Heterozygous COL4A3 Variants in Histologically Diagnosed Focal Segmental Glomerulosclerosis. Front Pediatr 2018; 6:171. [PMID: 29946535 PMCID: PMC6007128 DOI: 10.3389/fped.2018.00171] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 05/24/2018] [Indexed: 01/15/2023] Open
Abstract
Introduction: Steroid-resistant nephrotic syndrome (SRNS) is one of the most frequent causes for chronic kidney disease in childhood. In ~30% of these cases a genetic cause can be identified. The histological finding in SRNS is often focal segmental glomerulosclerosis (FSGS). In rare cases, however, pathogenic variants in genes associated with Alport syndrome can be identified in patients with the histological finding of FSGS. Materials and Methods: Clinical information was collected out of clinical reports and medical history. Focused molecular genetic analysis included sequencing of COL4A5 and COL4A3 in the index patient. Segregation analysis of identified variants was performed in the parents and children of the index patient. Results: The female index patient developed mild proteinuria and microscopic hematuria in childhood (12 years of age). The histological examination of the kidney biopsies performed at the age of 21, 28, and 32 years showed findings partly compatible with FSGS. However, immunosuppressive treatment of the index patient did not lead to a sufficient reduction of in part nephrotic-range proteinuria. After the patient developed hearing impairment at the age of 34 years and her daughter was diagnosed with microscopic hematuria at the age of 6 years, re-examination of the index's kidney biopsies by electron microscopy revealed textural changes of glomerular basement membrane compatible with Alport syndrome. Molecular genetic analysis identified two missense variants in COL4A3 in a compound heterozygous state with maternal and paternal inheritance. One of them is a novel variant that was also found in the 6 year old daughter of the index patient who presented with microscopic hematuria. Discussion: We were able to show that a novel variant combined with a previously described variant in compound heterozygous state resulted in a phenotype that was histologically associated with FSGS. Molecular genetic analysis therefore can be essential to solve difficult cases that show an unusual appearance and therefore improve diagnostic accuracy. Additionally, unnecessary and inefficient treatment with multiple side effects can be avoided.
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Affiliation(s)
- Matthias C Braunisch
- Department of Nephrology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.,Institute of Human Genetics, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Maike Büttner-Herold
- Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-University, Erlangen, Germany
| | - Roman Günthner
- Department of Nephrology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.,Institute of Human Genetics, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Robin Satanovskij
- Department of Nephrology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.,Institute of Human Genetics, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Korbinian M Riedhammer
- Department of Nephrology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany.,Institute of Human Genetics, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Pierre-Maurice Herr
- Institute of Human Genetics, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Hanns-Georg Klein
- Center for Human Genetics and Laboratory Diagnostics Dr. Klein, Dr. Rost and Colleagues, Martinsried, Germany
| | - Dagmar Wahl
- Center for Human Genetics and Laboratory Diagnostics Dr. Klein, Dr. Rost and Colleagues, Martinsried, Germany
| | - Claudius Küchle
- Department of Nephrology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Lutz Renders
- Department of Nephrology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Uwe Heemann
- Department of Nephrology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Christoph Schmaderer
- Department of Nephrology, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
| | - Julia Hoefele
- Institute of Human Genetics, Klinikum Rechts der Isar, Technical University of Munich, Munich, Germany
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Yang Y, Zhao L, Xiao L, Liang Y, Wang C, Fu X, Zhu X, Yuan S, Zhu J, Zhu X, Liu Y, Li J, Luo J, Liu F, Sun L. Chlormethine Hydrochloride is Not Inferior to Tacrolimus in Treating Steroid-Resistant Nephrotic Syndrome. Kidney Blood Press Res 2018; 43:68-79. [DOI: 10.1159/000486911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 01/18/2018] [Indexed: 11/19/2022] Open
Abstract
<b><i>Background/Aims:</i></b> The present study aimed to explore the equivalence of CHL and tacrolimus (TAC), despite reports regarding the efficacy and safety of TAC in treating SRNS patients. <b><i>Methods:</i></b> A retrospective cohort study of CHL or TAC treatment was performed by collecting the medical records of SRNS patients with a pathological classification of focal segmental glomurular sclerosis (FSGS) or membranous nephropathy (MN) from December 2008 to December 2014 in a 3A grade hospital in southern China. The treatment regimen includes 6 months of induction therapy and a subsequent 6 to 30 months of maintenance therapy, which were evaluated by the scheduled follow-up and the detection of proteinuria and serum creatinine levels. The treatment outcomes were classified as complete remission, partial remission or no remission. <b><i>Results:</i></b> In a total of 146 SRNS patients, CHL treatment showed a higher proportion of complete remission (27.8% vs 14.9%) or partial remission (52.8% vs 37.8%) compared to TAC treatment (<i>P</i> < 0.10) at the stage of induction therapy. The CHL treatment of SRNS patients with FSGS showed better efficacy than treatment of the TAC group, but the difference of efficacy in the pathological type of MN between CHL and TAC group was not significant (<i>P</i> > 0.10). During maintenance therapy, the difference between the CHL and TAC groups was not significant in the SRNS patients with FSGS or MN (<i>P</i> > 0.10). In addition, the difference of adverse effects between CHL and TAC group was not significant (<i>P</i> > 0.10), although there was a slightly higher proportion of nausea and vomiting in the CHL group. <b><i>Conclusion:</i></b> The non-inferior efficacy of CHL treatment on the SRNS patients with FSGS or MN compared to TAC treatment, which highlighted CHL can be considered to be alternative treatment for SRNS patients in the clinical setting.
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Feltran LS, Varela P, Silva ED, Veronez CL, Franco MC, Filho AP, Camargo MF, Koch Nogueira PC, Pesquero JB. Targeted Next-Generation Sequencing in Brazilian Children With Nephrotic Syndrome Submitted to Renal Transplant. Transplantation 2017; 101:2905-2912. [PMID: 28658201 DOI: 10.1097/tp.0000000000001846] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND The aims of this study were to identify the genetic mutations profile in Brazilian children with nephrotic syndrome (NS) and to determine a genotype-phenotype correlation in this disease. METHODS Next-generation sequencing and mutation analysis were performed on 24 genes related to NS in a cross-sectional study involving 95 children who underwent kidney transplantation due to NS, excluding congenital cases. RESULTS A total of 149 variants were identified in 22 of 24 sequenced genes. The mutations were classified as pathogenic, likely pathogenic, likely benign and benign per the chance of causing the disease. NPHS2 was the most common mutated gene. We identified 8 (8.4%) patients with hereditary NS and 5 (5%) patients with probably genetically caused NS. COL4A3-5 variants were found as well, but it is not clear whether they should be considered isolated FSGS or simply a misdiagnosed type of the Alport spectrum. Considering the clinical results, hereditary NS patients presented a tendency to early disease onset when compared with the other groups (P = 0.06) and time to end stage renal disease (ESRD) was longer in this group (P = 0.03). No patients from hereditary NS group had NS recurrence after transplantation. CONCLUSIONS This is the first study in children with steroid-resistant NS who underwent kidney transplantation using next-generation sequencing. Considering our results, we believe this study has shed some light to the uncertainties of genotype-phenotype correlation in NS, where several genes cooperate to produce or even to modify the course of the disease.
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Affiliation(s)
- Luciana S Feltran
- Nephrology Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Patricia Varela
- Biophysics Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Elton Dias Silva
- Biophysics Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Camila Lopes Veronez
- Biophysics Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Maria Carmo Franco
- Nephrology Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Alvaro Pacheco Filho
- Nephrology Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Maria Fernanda Camargo
- Nephrology Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Paulo Cesar Koch Nogueira
- Pediatrics Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Joao Bosco Pesquero
- Biophysics Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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Sen ES, Dean P, Yarram-Smith L, Bierzynska A, Woodward G, Buxton C, Dennis G, Welsh GI, Williams M, Saleem MA. Clinical genetic testing using a custom-designed steroid-resistant nephrotic syndrome gene panel: analysis and recommendations. J Med Genet 2017; 54:795-804. [PMID: 28780565 PMCID: PMC5740557 DOI: 10.1136/jmedgenet-2017-104811] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/27/2017] [Accepted: 06/29/2017] [Indexed: 01/16/2023]
Abstract
BACKGROUND There are many single-gene causes of steroid-resistant nephrotic syndrome (SRNS) and the list continues to grow rapidly. Prompt comprehensive diagnostic testing is key to realising the clinical benefits of a genetic diagnosis. This report describes a bespoke-designed, targeted next-generation sequencing (NGS) diagnostic gene panel assay to detect variants in 37 genes including the ability to identify copy number variants (CNVs). METHODS This study reports results of 302 patients referred for SRNS diagnostic gene panel analysis. Phenotype and clinical impact data were collected using a standard proforma. Candidate variants detected by NGS were confirmed by Sanger sequencing/Multiplex Ligation-dependent Probe Amplification with subsequent family segregation analysis where possible. RESULTS Clinical presentation was nephrotic syndrome in 267 patients and suspected Alport syndrome (AS) in 35. NGS panel testing determined a likely genetic cause of disease in 44/220 (20.0%) paediatric and 10/47 (21.3%) adult nephrotic cases, and 17/35 (48.6%) of haematuria/AS patients. Of 71 patients with genetic disease, 32 had novel pathogenic variants without a previous disease association including two with deletions of one or more exons of NPHS1 or NPHS2. CONCLUSION Gene panel testing provides a genetic diagnosis in a significant number of patients presenting with SRNS or suspected AS. It should be undertaken at an early stage of the care pathway and include the ability to detect CNVs as an emerging mechanism for genes associated with this condition. Use of clinical genetic testing after diagnosis of SRNS has the potential to stratify patients and assist decision-making regarding management.
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Affiliation(s)
- Ethan S Sen
- Bristol Renal, School of Clinical Sciences, University of Bristol, Bristol, UK
- Bristol Royal Hospital for Children, Bristol, UK
| | - Philip Dean
- Bristol Genetics Laboratory, Southmead Hospital, Bristol, UK
| | | | | | - Geoff Woodward
- Bristol Genetics Laboratory, Southmead Hospital, Bristol, UK
| | - Chris Buxton
- Bristol Genetics Laboratory, Southmead Hospital, Bristol, UK
| | - Gemma Dennis
- Bristol Genetics Laboratory, Southmead Hospital, Bristol, UK
| | - Gavin I Welsh
- Bristol Renal, School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Maggie Williams
- Bristol Genetics Laboratory, Southmead Hospital, Bristol, UK
| | - Moin A Saleem
- Bristol Renal, School of Clinical Sciences, University of Bristol, Bristol, UK
- Bristol Royal Hospital for Children, Bristol, UK
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Zhang H, Wang F, Liu X, Zhong X, Yao Y, Xiao H. Steroid-resistant nephrotic syndrome caused by co-inheritance of mutations at NPHS1 and ADCK4 genes in two Chinese siblings. Intractable Rare Dis Res 2017; 6:299-303. [PMID: 29259860 PMCID: PMC5735285 DOI: 10.5582/irdr.2017.01037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Hereditary nephrotic syndrome often presents with steroid-resistance and onset within the first year of life. Mutations in genes highly expressed in podocytes have been found in two thirds of these patients, especially NPHS1 and NPHS2 among at least 29 genetic causes that have been discovered. We reported two siblings with steroid-resistant nephrotic syndrome caused by co-inheritance of mutations at NPHS1 (c.1339G>A, p.E447K) and ACDK4 (c.748G>C, p.D250H) genes. The siblings presented with steroid-resistant nephrotic syndrome and pathological lesions of focal segmental glomerulosclerosis (FSGS), while the elder sister also developed hypertension, renal failure and cardiac dysfunction.
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Affiliation(s)
- Hongwen Zhang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Fang Wang
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Xiaoyu Liu
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Xuhui Zhong
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Yong Yao
- Department of Pediatric, Peking University First Hospital, Beijing, China
| | - Huijie Xiao
- Department of Pediatric, Peking University First Hospital, Beijing, China
- Address correspondence to: Dr. Huijie Xiao, Department of Pediatric, Peking University First Hospital, No.1 Xi An Men Da Jie, Beijing 100034, China. E-mail:
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Liu J, Wang W. Genetic basis of adult-onset nephrotic syndrome and focal segmental glomerulosclerosis. Front Med 2017; 11:333-339. [PMID: 28776307 DOI: 10.1007/s11684-017-0564-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/02/2017] [Indexed: 12/22/2022]
Abstract
Nephrotic syndrome (NS) is one of the most common glomerular diseases with signs of nephrosis, heavy proteinuria, hypoalbuminemia, and edema. Dysfunction of glomerular filtration barrier causes protein loss through the kidneys. Focal segmental glomerulosclerosis (FSGS) accounts for nearly 20% of NS among children and adults. Adult-onset FSGS/NS is often associated with low response to steroid treatment and immunosuppressive medication and poor renal survival. Several genes involved in NS and FSGS have been identified by linkage analysis and next-generation sequencing. Most of these genes encode proteins and are highly expressed in glomerular podocytes, which play crucial roles in slit-diaphragm signaling, regulation of actin cytoskeleton dynamics and maintenance of podocyte integrity, and cell-matrix interactions. In this review, we focus on the recently identified genes in the adult-onset NS and FSGS and discuss clinical significance of screening of these genes.
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Affiliation(s)
- Jian Liu
- Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.,Department of Nephrology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Weiming Wang
- Institute of Nephrology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China. .,Department of Nephrology, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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Ars E, Torra R. Rare diseases, rare presentations: recognizing atypical inherited kidney disease phenotypes in the age of genomics. Clin Kidney J 2017; 10:586-593. [PMID: 28980669 PMCID: PMC5622904 DOI: 10.1093/ckj/sfx051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 05/03/2017] [Indexed: 12/11/2022] Open
Abstract
A significant percentage of adults (10%) and children (20%) on renal replacement therapy have an inherited kidney disease (IKD). The new genomic era, ushered in by the next generation sequencing techniques, has contributed to the identification of new genes and facilitated the genetic diagnosis of the highly heterogeneous IKDs. Consequently, it has also allowed the reclassification of diseases and has broadened the phenotypic spectrum of many classical IKDs. Various genetic, epigenetic and environmental factors may explain ‘atypical’ phenotypes. In this article, we examine different mechanisms that may contribute to phenotypic variability and also provide case examples that illustrate them. The aim of the article is to raise awareness, among nephrologists and geneticists, of rare presentations that IKDs may show, to facilitate diagnosis.
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Affiliation(s)
- 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
| | - Roser Torra
- Inherited Kidney Disorders, 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
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NPHS2 Mutations: A Closer Look to Latin American Countries. BIOMED RESEARCH INTERNATIONAL 2017; 2017:7518789. [PMID: 28785586 PMCID: PMC5529630 DOI: 10.1155/2017/7518789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 06/02/2017] [Accepted: 06/08/2017] [Indexed: 01/10/2023]
Abstract
Nephrotic syndrome is one of the most common kidney pathologies in childhood, being characterized by proteinuria, edema, and hypoalbuminemia. In clinical practice, it is divided into two categories based on the response to steroid therapy: steroid-sensitive and steroid resistant. Inherited impairments of proteins located in the glomerular filtration barrier have been identified as important causes of nephrotic syndrome, with one of these being podocin, coded by NPHS2 gene. NPHS2 mutations are the most frequent genetic cause of steroid resistant nephrotic syndrome. The aim of this review is to update the list of NPHS2 mutations reported between June 2013 and February 2017, with a closer look to mutations occurring in Latin American countries.
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Kino J, Tsukaguchi H, Kimata T, Nguyen HT, Nakano Y, Miyake N, Matsumoto N, Kaneko K. Nephron development and extrarenal features in a child with congenital nephrotic syndrome caused by null LAMB2 mutations. BMC Nephrol 2017; 18:220. [PMID: 28683731 PMCID: PMC5501564 DOI: 10.1186/s12882-017-0632-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 06/22/2017] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Congenital nephrotic syndrome (CNS) is a rare disorder caused by various structural and developmental defects of glomeruli. It occurs typically as an isolated kidney disorder but associates sometimes with other systemic, extrarenal manifestations. CASE PRESENTATIONS An infant presented with severe CNS, which progressed rapidly to renal failure at age of 3 months and death at 27 months. The clinical phenotypes and genetic causes were studied, including the renal pathology at autopsy. Besides the CNS, the affected child had remarkable right-side predominant eye-ball hypoplasia with bilateral anterior chamber dysgenesis (microcoria). Brain MRI revealed grossly normal development in the cerebrum, cerebellum, and brain stem. Auditory brainstem responses were bilaterally blunted, suggesting a defective auditory system. At autopsy, both kidneys were mildly atrophied with persistent fetal lobulation. Microscopic examination showed a diffuse global sclerosis. However, despite of the smaller size of glomeruli, the nephron number remained similar to that of the age-matched control. Whole-exome sequencing revealed that the affected child was compound heterozygous for novel truncating LAMB2 mutations: a 4-bp insertion (p.Gly1693Alafs*8) and a splicing donor-site substitution (c.1225 + 1G > A), presumably deleting the coiled-coil domains that form the laminin 5-2-1 heterotrimer complex. CONCLUSIONS Our case represents a variation of Pierson syndrome that accompanies CNS with unilateral ocular hypoplasia. The average number but smaller glomeruli could reflect either mal-development or glomerulosclerosis. Heterogeneous clinical expression of LAMB2 defects may associate with the difference in fetal β1 subtype compensation among affected tissues. Further study is necessary to evaluate incidence and features of auditory defect under LAMB2 deficiency.
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Affiliation(s)
- Jiro Kino
- Department of Pediatrics, Kansai Medical University, 2-5-1 Shimachi, Hirakata, Osaka, 573-1010, Japan
| | - Hiroyasu Tsukaguchi
- Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi Hirakata, Osaka, 573-1010, Japan.
| | - Takahisa Kimata
- Department of Pediatrics, Kansai Medical University, 2-5-1 Shimachi, Hirakata, Osaka, 573-1010, Japan
| | - Huan Thanh Nguyen
- Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi Hirakata, Osaka, 573-1010, Japan
| | - Yorika Nakano
- Department of Pathology and Laboratory Medicine, Kansai Medical University, Osaka, Japan.,Present Address: Department of Histopathology and Cytology, Japanese Red Cross Kyoto Daini Hospital, Kyoto, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Kazunari Kaneko
- Department of Pediatrics, Kansai Medical University, 2-5-1 Shimachi, Hirakata, Osaka, 573-1010, Japan
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Wang F, Zhang Y, Mao J, Yu Z, Yi Z, Yu L, Sun J, Wei X, Ding F, Zhang H, Xiao H, Yao Y, Tan W, Lovric S, Ding J, Hildebrandt F. Spectrum of mutations in Chinese children with steroid-resistant nephrotic syndrome. Pediatr Nephrol 2017; 32:1181-1192. [PMID: 28204945 PMCID: PMC5478193 DOI: 10.1007/s00467-017-3590-y] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 12/06/2016] [Accepted: 12/23/2016] [Indexed: 01/21/2023]
Abstract
BACKGROUND The aim of this study was to elucidate whether genetic screening test results of pediatric patients with steroid-resistant nephrotic syndrome (SRNS) vary with ethnicity. METHODS Using high-throughput DNA sequencing, 28 nephrotic syndrome-related genes were analyzed in 110 chil-dren affected by SRNS and 10 children with isolated proteinuria enrolled by 5 centers in China (67 boys, 53 girls). Their age at disease onset ranged from 1 day to 208 months (median, 48.8 months). Patients were excluded if their age at onset of disease was over 18 years or if they were diagnosed as having Alport syndrome. RESULTS A genetic etiology was identified in 28.3% of our cohort and the likelihood of establishing a genetic diagnosis decreased as the age at onset of nephrotic syndrome increased. The most common mutated genes were ADCK4 (6.67%), NPHS1 (5.83%), WT1 (5.83%), and NPHS2 (3.33%), and the difference in the frequencies of ADCK4 and NPHS2 mutations between this study and a study on monogenic causes of SRNS in the largest international cohort of 1,783 different families was significant. A case of congenital nephrotic syndrome was attributed to a homozygous missense mutation in ADCK4, and a de novo missense mutation in TRPC6 was detected in a case of infantile nephrotic syndrome. CONCLUSIONS Our results showed that, in the first and the largest multicenter cohort of Chinese pediatric SRNS reported to date, ADCK4 is the most common causative gene, whereas there is a low prevalence of NPHS2 mutations. Our data indicated that the genetic testing results for pediatric SRNS patients vary with different ethnicities, and this information will help to improve management of the disease in clinical practice.
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Affiliation(s)
- Fang Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Yanqin Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Jianhua Mao
- Department of Nephrology, The Children Hospital of Zhejiang University School of Medicine, Hangzhou, P. R. China
| | - Zihua Yu
- Department of Pediatrics, Fuzhou Dongfang Hospital, Fuzhou, P. R. China
| | - Zhuwen Yi
- Department of Pediatrics, The second Xiangya Hospital, Central South University, Changsha, P. R. China
| | - Li Yu
- Department of Pediatrics, Guangzhou First People’s Hospital, Guangzhou, P. R. China
| | - Jun Sun
- Binhai Genomics Institute, Tianjin Translational Genomics Center, BGI-Tianjin, BGI-shenzhen, Tianjin, P. R. China,BGI-Shenzhen, Shenzhen, P. R. China
| | - Xiuxiu Wei
- Binhai Genomics Institute, Tianjin Translational Genomics Center, BGI-Tianjin, BGI-shenzhen, Tianjin, P. R. China,BGI-Shenzhen, Shenzhen, P. R. China
| | - Fangrui Ding
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Hongwen Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Huijie Xiao
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Yong Yao
- Department of Pediatrics, Peking University First Hospital, Beijing, P. R. China
| | - Weizhen Tan
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Svjetlana Lovric
- Division of Nephrology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, No. 1, Xi An Men Da Jie, Beijing, 100034, People's Republic of China.
| | - Friedhelm Hildebrandt
- Division of Nephrology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Enders 561, Boston, MA, 02115, USA.
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Dogra S, Kaskel F. Steroid-resistant nephrotic syndrome: a persistent challenge for pediatric nephrology. Pediatr Nephrol 2017; 32:965-974. [PMID: 27783158 DOI: 10.1007/s00467-016-3459-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 06/23/2016] [Accepted: 06/24/2016] [Indexed: 12/19/2022]
Abstract
Steroid-resistant nephrotic syndrome remains a challenge to treat, but various efforts are underway to better understand the pathogenesis and improve patient outcomes. This review provides an update on the newer advances in understanding the molecular etiologies for a variety of podocyte abnormalities, potential circulating factors that may initiate and sustain the steroid-resistant state, genetic mutations, and precision medicine treatment modalities in this continuously perplexing disorder.
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Affiliation(s)
- Samriti Dogra
- Division of Pediatric Nephrology, Department of Pediatrics, Connecticut Children's Medical Center, 282 Washington Street, Hartford, CT, 06095, USA.
| | - Frederick Kaskel
- Division of Pediatric Nephrology, Department of Pediatrics, Children's Hospital at Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
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