A genomic association study revealing subphenotypes of childhood steroid-sensitive nephrotic syndrome in a larger genomic sequencing cohort

Dissecting the genetic components that contribute to the two main subphenotypes of steroid-sensitive nephrotic syndrome(SSNS)using genome-wide association studies(GWAS)strategy is important for understanding the disease.We conducted a multicenter cohort study(360 patients and 1835 controls)combined with a GWAS strategy to identify susceptibility var-iants associated with the following two subphenotypes of ssNS:steroid-sensitive nephrotic syn-drome without relapse(SSNswR,181 patients)and steroid-dependent/frequent relapse nephrotic syndrome(SDNS/FRNS,179 patients).The distribution of two single-nucleotide poly-morphisms(SNPs)in ANKRD36 and ALPG was significant between SSNSWR and healthy controls,and that of two SNPs in GAD1 and HLA-DQA1 was significant between SDNS/FRNS and healthy controls.Interestingly,rs1047989 in HLA-DQA1 was a candidate locus for SDNS/FRNS but not for SSNSWR.No significant SNPs were observed between SSNSWR and SDNS/FRNS.Meanwhile,chromosome 2:171713702 in GAD1 was associated with a greater steroid dose(>0.75 mg/kg/d)upon relapse to first remission in patients with SDNS/FRNS(odds ratio=3.14;95%confidence interval,0.97-9.87;P=0.034).rs117014418 in APOL4 was significantly associated with a decrease in eGFR of greater than 20%compared with the baseline in SDNS/FRNS patients(P=0.0001).Protein-protein intersection network construction suggested that HLA-DQA1 and HLA-DQB1 function together through GSDMA.Thus,SSNSWR belongs to non-HLA region-dependent nephropathy,and the HLA-DQA/DQB region is likely strongly associated with dis-ease relapse,especially in SDNS/FRNS.The study provides a novel approach for the GWAS strategy of SsNS and contributes to our understanding of the pathological mechanisms of SSNSWRandSDNS/FRNS.

Association between HLA alleles and sub-phenotype of childhood steroid-sensitive nephrotic syndrome

BACKGROUND Few studies have addressed the effects of human leukocyte antigen(HLA)alleles on different clinical sub-phenotypes in childhood steroid-sensitive nephrotic syndrome(SSNS),including SSNS without recurrence(SSNSWR)and steroid-dependent nephrotic syndrome/frequently relapse nephrotic syndrome(SDNS/FRNS).In this study,we investigated the relationship between HLA system and children with SSNSWR and SDNS/FRNS and clarified the value of HLA allele detection for precise typing of childhood SSNS.METHODS A total of 241 Chinese Han individuals with SSNS were genotyped using GenCap-WES Capture Kit,and four-digit resolution HLA alleles were imputed from available Genome Wide Association data.The distribution and carrying frequency of HLA alleles in SSNSWR and SDNS/FRNS were investigated.Additionally,logistic regression and mediating effects were used to examine the relationship between risk factors for disease process and HLA system.RESULTS Compared with SSNSWR,significantly decreased serum levels of complement 3(C3)and complement 4(C4)at onset were detected in SDNS/FRNS(C3,P<0.001;C4,P=0.018).The average time to remission after sufficient initial steroid treatment in SDNS/FRNS was significantly longer than that in SSNSWR(P=0.0001).Low level of C4 was further identified as an independent risk factor for SDNS/FRNS(P=0.008,odds ratio=0.174,95% confidence interval 0.048-0.630).The HLA-A*11:01 allele was independently associated with SSNSWR and SDNS/FRNS(P=0.0012 and P=0.0006,respectively).No significant HLA alleles were detected between SSNSWR and SDNS/FRNS.In addition,a mediating effect among HLA-I alleles(HLA-B*15:11,HLA-B*44:03 and HLA-C*07:06),C4 level and SDNS/FRNS was identified.CONCLUSIONS HLA-I alleles provide novel genetic markers for SSNSWR and SDNS/FRNS.HLA-I antigens may be involved in steroid dependent or frequent relapse in children with SSNS as mediators of immunoregulation.

Whole-exome sequencing of a multicenter cohort identifies genetic changes associated with clinical phenotypes in pediatric nephrotic syndrome

Understanding the association between the genetic and clinical phenotypes in children with nephrotic syndrome(NS)of different etiologies is critical for early clinical guidance.We employed whole-exome sequencing(WES)to detect monogenic causes of NS in a multicenter cohort of 637 patients.In this study,a genetic cause was identified in 30.0%of the idiopathic steroid-resistant nephrotic syndrome(SRNS)patients.Other than congenital nephrotic syndrome(CNS),there were no significant differences in the incidence of monogenic diseases based on the age at manifestation.Causative mutations were detected in 39.5%of patients with focal segmental glomerulosclerosis(FSGS)and 9.2%of those with minimal change disease(MCD).In terms of the patterns in patients with different types of steroid resistance,a single gene mutation was identified in 34.8%of patients with primary resistance,2.9%with secondary resistance,and 71.4%of children with multidrug resistance.Among the various intensified immunosuppressive therapies,tacrolimus(TAC)showed the highest response rate,with 49.7%of idiopathic SRNS patients achieving complete remission.Idiopathic SRNS patients with monogenic disease showed a similar multidrug resistance pattern,and only 31.4%of patients with monogenic disease achieved a partial remission on TAC.During an average 4.1-year follow-up,21.4%of idiopathic SRNS patients with monogenic disease progressed to end-stage renal disease(ESRD).Collectively,this study provides evidence that genetic testing is necessary for presumed steroid-resistant and idiopathic SRNS patients,especially those with primary and/or multidrug resistance.