Steroid-resistant nephrotic syndrome in children: A mini-review on genetic mechanisms, predictive biomarkers and pharmacotherapy strategies

2020 ◽  
Vol 26 ◽  
Author(s):  
Hong-Li Guo ◽  
Ling Li ◽  
Ze-Yue Xu ◽  
Xia Jing ◽  
Ying Xia ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Molecular Mechanisms ◽  
Single Gene ◽  
Predictive Biomarkers ◽  
Steroid Resistant ◽  
Steroid Resistant Nephrotic Syndrome ◽  
Genes Encoding ◽  
Standardized Treatment ◽  
Associated Proteins ◽  
Genetic Mechanisms

: 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 about 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 were 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.

scholarly journals P1802EVALUATION OF THE GENETICAL FEATURES AFFECTING THE RENAL OUTCOMES IN CHILDREN WITH STEROID RESISTANT NEPHROTIC SYNDROME

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Elif Comak ◽  
Aslı Toylu ◽  
Ugur Bilge ◽  
Gülsah Kaya Aksoy ◽  
Mustafa Koyun ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Target Genes ◽  
Immunosuppressive Agents ◽  
Gene Panel ◽  
Sequencing Analysis ◽  
Single Nucleotide Variants ◽  
Steroid Resistant ◽  
Steroid Resistant Nephrotic Syndrome ◽  
Genes Encoding ◽  
Renal Prognosis

Abstract Background and Aims Nephrotic syndrome in childhood is characterized by proteinuria, hypoalbuminemia, edema, and hyperlipidemia. Although most children respond to glucocorticoid therapy, approximately 10% of patients turn out to be steroid resistant (steroid-resistant nephrotic syndrome [SRNS]). Although several studies in children with SRNS have shown that mutations in genes encoding proteins in the podocyte skeleton may be responsible for the etiology in only one-third of cases, the genetic features related with renal prognosis and response to immunosuppressive agents are not fully recognized. The aim of this study was to investigate the genomic alterations associated with renal prognosis and resistance to immunosuppression in children with SRNS. Method The children with SRNS were enrolled in this study. Custom gene panel was designed for next-generation sequencing analysis of more than 20 target genes (ABCB1, ABCC2, CTLA4, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, FOXP3, GSTP1, IMPDH1, IMPDH2, NOS3, NR3C1, SLCO1B1, SLCO1B3, TPMT, UGT1A9, UGT2B7) and 200 single nucleotide variants (SNVs) which were reported as implicated in renal prognosis of nephrotic syndrome. The target gene panel was enriched for drug metabolism regulating transporters and enzymes. Results A total of 25 children, 16 boys (64%), median age at last visit 17.5 years (13-18 years), median age at diagnosis 7.5 years (2-15), median follow-up 9.58±4.54 years, were included in the study. All patients were diagnosed focal segmental glomerulosclerosis on renal biopsy.

scholarly journals ADCK4 Deficiency Destabilizes the Coenzyme Q Complex, Which Is Rescued by 2,4-Dihydroxybenzoic Acid Treatment

2020 ◽  
Vol 31 (6) ◽  
pp. 1191-1211 ◽  
Author(s):  
Eugen Widmeier ◽  
Seyoung Yu ◽  
Anish Nag ◽  
Youn Wook Chung ◽  
Makiko Nakayama ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Knockout Mice ◽  
Molecular Mechanisms ◽  
Coenzyme Q ◽  
Mass Spectrometry Analysis ◽  
Dihydroxybenzoic Acid ◽  
Mitochondrial Potential ◽  
Steroid Resistant ◽  
Steroid Resistant Nephrotic Syndrome

BackgroundMutations in ADCK4 (aarF domain containing kinase 4) generally manifest as steroid-resistant nephrotic syndrome and induce coenzyme Q10 (CoQ10) deficiency. However, the molecular mechanisms underlying steroid-resistant nephrotic syndrome resulting from ADCK4 mutations are not well understood, largely because the function of ADCK4 remains unknown.MethodsTo elucidate the ADCK4’s function in podocytes, we generated a podocyte-specific, Adck4-knockout mouse model and a human podocyte cell line featuring knockout of ADCK4. These knockout mice and podocytes were then treated with 2,4-dihydroxybenzoic acid (2,4-diHB), a CoQ10 precursor analogue, or with a vehicle only. We also performed proteomic mass spectrometry analysis to further elucidate ADCK4’s function.ResultsAbsence of Adck4 in mouse podocytes caused FSGS and albuminuria, recapitulating features of nephrotic syndrome caused by ADCK4 mutations. In vitro studies revealed that ADCK4-knockout podocytes had significantly reduced CoQ10 concentration, respiratory chain activity, and mitochondrial potential, and subsequently displayed an increase in the number of dysmorphic mitochondria. However, treatment of 3-month-old knockout mice or ADCK4-knockout cells with 2,4-diHB prevented the development of renal dysfunction and reversed mitochondrial dysfunction in podocytes. Moreover, ADCK4 interacted with mitochondrial proteins such as COQ5, as well as cytoplasmic proteins such as myosin and heat shock proteins. Thus, ADCK4 knockout decreased the COQ complex level, but overexpression of ADCK4 in ADCK4-knockout podocytes transfected with wild-type ADCK4 rescued the COQ5 level.ConclusionsOur study shows that ADCK4 is required for CoQ10 biosynthesis and mitochondrial function in podocytes, and suggests that ADCK4 in podocytes stabilizes proteins in complex Q in podocytes. Our study also suggests a potential treatment strategy for nephrotic syndrome resulting from ADCK4 mutations.

scholarly journals A Single-Gene Cause in 29.5% of Cases of Steroid-Resistant Nephrotic Syndrome

2014 ◽  
Vol 26 (6) ◽  
pp. 1279-1289 ◽  
Author(s):  
Carolin E. Sadowski ◽  
Svjetlana Lovric ◽  
Shazia Ashraf ◽  
Werner L. Pabst ◽  
Heon Yung Gee ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Single Gene ◽  
Steroid Resistant ◽  
Steroid Resistant Nephrotic Syndrome

scholarly journals Polypoid Change of the Glomerular Basement Membrane in a Child with Steroid Resistant Nephrotic Syndrome and ARHGAP24 Mutation: A Case Report

2016 ◽  
Vol 9 (1) ◽  
pp. 88-93 ◽  
Author(s):  
Anna Francis ◽  
John Burke ◽  
Leo Francis ◽  
Steven McTaggart ◽  
Andrew Mallett
Keyword(s):  
Nephrotic Syndrome ◽  
Basement Membrane ◽  
Gene Product ◽  
Glomerular Basement Membrane ◽  
Steroid Resistant ◽  
Steroid Resistant Nephrotic Syndrome ◽  
Membrane Ruffling ◽  
Genes Encoding ◽  
Important Player

Background: Steroid resistant nephrotic syndrome (SRNS) is increasingly recognised to have a genetic basis following the identification of a number of mutations within genes encoding podocyte and basement membrane proteins. The ARHGAP24 gene product is a recently recognised important player in podocyte interaction with the glomerular basement membrane. The ARHGAP24 gene encodes a protein involved in regulating cell motility, membrane structure and polarity. Mutations in the gene have been shown in vitro to cause cell membrane ruffling. Case Presentation: We report a novel missense mutation in exon 4 (c.[284G>A]; p.[Arg95Gln]) of the ARHGAP24 gene in a child that presented with SRNS at four years of age. Renal biopsy demonstrated unusual polypoid changes of the glomerular basement membrane (GBM). Conclusion: We propose this novel ARHGAP24 mutation as causative for SRNS associated with unusual polypoid basement membrane changes. These biopsy findings, in association with ARHGAP24 mutation and clinical nephrotic syndrome are a novel finding. This finding may advance the understanding of ARHGAP24 gene product function.

scholarly journals Look Alike, Sound Alike: Phenocopies in Steroid-Resistant Nephrotic Syndrome

2020 ◽  
Vol 17 (22) ◽  
pp. 8363
Author(s):  
Francesca Becherucci ◽  
Samuela Landini ◽  
Luigi Cirillo ◽  
Benedetta Mazzinghi ◽  
Paola Romagnani
Keyword(s):  
Nephrotic Syndrome ◽  
Genetic Testing ◽  
Clinical Management ◽  
Reverse Genetics ◽  
Molecular Mechanisms ◽  
Young Patients ◽  
Diagnostic Procedures ◽  
Steroid Resistant ◽  
Steroid Resistant Nephrotic Syndrome ◽  
End Stage

Steroid-resistant nephrotic syndrome (SRNS) is a clinical picture defined by the lack of response to standard steroid treatment, frequently progressing toward end-stage kidney disease. The genetic basis of SRNS has been thoroughly explored since the end of the 1990s and especially with the advent of next-generation sequencing. Genetic forms represent about 30% of cases of SRNS. However, recent evidence supports the hypothesis that “phenocopies” could account for a non-negligible fraction of SRNS patients who are currently classified as non-genetic, paving the way for a more comprehensive understanding of the genetic background of the disease. The identification of phenocopies is mandatory in order to provide patients with appropriate clinical management and to inform therapy. Extended genetic testing including phenocopy genes, coupled with reverse phenotyping, is recommended for all young patients with SRNS to avoid unnecessary and potentially harmful diagnostic procedures and treatment, and for the reclassification of the disease. The aim of this work is to review the main steps of the evolution of genetic testing in SRNS, demonstrating how a paradigm shifting from “forward” to “reverse” genetics could significantly improve the identification of the molecular mechanisms of the disease, as well as the overall clinical management of affected patients.

A rare cause of steroid-resistant nephrotic syndrome in a child: Answers

2019 ◽  
Vol 35 (4) ◽  
pp. 621-623
Author(s):  
Lale Guliyeva ◽  
Yılmaz Tabel ◽  
Ali Düzova ◽  
Nusret Akpolat ◽  
Seza Özen ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Steroid Resistant ◽  
Steroid Resistant Nephrotic Syndrome

Whole-Exome Sequencing Solved over 2-Decade Kidney Disease Enigma

Nephron ◽  
2021 ◽  
pp. 1-6
Author(s):  
Suramath Isaranuwatchai ◽  
Ankanee Chanakul ◽  
Chupong Ittiwut ◽  
Chalurmpon Srichomthong ◽  
Vorasuk Shotelersuk ◽  
...  
Keyword(s):  
Nephrotic Syndrome ◽  
Kidney Disease ◽  
Exome Sequencing ◽  
Whole Exome Sequencing ◽  
Treatment Plan ◽  
Unknown Etiology ◽  
Pediatric Case ◽  
Steroid Resistant ◽  
Steroid Resistant Nephrotic Syndrome ◽  
Whole Exome

Chronic kidney disease of unknown etiology (CKDu) has been a problem in renal practice as indefinite diagnosis may lead to inappropriate management. Here, we report a 54-year-old father diagnosed with CKDu at 33 years old and his 8-year-old son with steroid-resistant nephrotic syndrome. Using whole-exome sequencing, both were found to be heterozygous for c.737G>A (p.Arg246Gln) in LMX1B. The diagnosis of LMX1B-associated nephropathy has led to changes in the treatment plan with appropriate genetic counseling. The previously reported cases with this particular mutation were also reviewed. Most children with LMX1B-associated nephropathy had nonnephrotic proteinuria with normal renal function. Interestingly, our pediatric case presented with steroid-resistant nephrotic syndrome at 8 years old and progressed to ESRD requiring peritoneal dialysis at the age of 15 years. Our report emphasized the need of genetic testing in CKDu for definite diagnosis leading to precise management.

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