Responsible genes in children with primary vesicoureteral reflux: findings from the Chinese Children Genetic Kidney Disease Database

Background Primary vesicoureteral reflux(VUR)is a common congenital anomaly of the kidney and urinary tract(CAKUT)in childhood.The present study identified the possible genetic contributions to primary VUR in children.Methods Patients with primary VUR were enrolled and analysed based on a national multi-center registration network(Chinese Children Genetic Kidney Disease Database,CCGKDD)that covered 23 different provinces/regions in China from 2014 to 2019.Genetic causes were sought using whole-exome sequencing(WES)or targeted-exome sequencing.Results A total of 379 unrelated patients(male:female 219:160)with primary VUR were recruited.Sixty-four(16.9%)children had extrarenal manifestations,and 165(43.5%)patients showed the coexistence of other CAKUT phenotypes.Eighty-eight patient(23.2%)exhibited impaired renal function at their last visit,and 18 of them(20.5%)developed ESRD at the median age of 7.0(IQR 0.9–11.4)years.A monogenic cause was identified in 28 patients(7.39%).These genes included PAX2(n=4),TNXB(n=3),GATA3(n=3),SLIT2(n=3),ROBO2(n=2),TBX18(n=2),and the other 11 genes(one gene for each patient).There was a significant difference in the rate of gene mutations between patients with or without extrarenal complications(14.1%vs.6%,P=0.035).The frequency of genetic abnormality was not statistically significant based on the coexistence of another CAKUT(9.6%vs.5.6%,P=0.139,Chi-square test)and the grade of reflux(9.4%vs.6.7%,P=0.429).Kaplan–Meier survival curve showed that the presence of genetic mutations did affect renal survival(Log-rank test,P=0.01).PAX2 mutation carriers(HR 5.1,95%CI 1.3–20.0;P=0.02)and TNXB mutation carriers(HR 20.3,95%CI 2.4–168.7;P=0.01)were associated with increased risk of progression to ESRD.Conclusions PAX2,TNXB,GATA3 and SLIT2 were the main underlying monogenic causes and accounted for up to 46.4%of monogenic VUR.Extrarenal complications and renal function were significantly related to the findings of genetic factors in children with primary VUR.Like other types of CAKUT,several genes may be responsible for isolated VUR.

Genetic Architecture of Childhood Kidney and Urological Diseases in China

Kidney disease is manifested in a wide variety of phenotypes,many of which have an important hereditary component.To delineate the genotypic and phenotypic spectrum of pediatric nephropathy,a multicenter registration system is being imple-mented based on the Chinese Children Genetic Kidney Disease Database(CCGKDD).In this study,all the patients with kidney and urological diseases were recruited from 2014 to 2020.Genetic analysis was conducted using exome sequencing for families with multiple affected individuals with nephropathy or clinical suspicion of a genetic kidney disease owing to early-onset or extrarenal features.The genetic diagnosis was confirmed in 883 of 2256(39.1%)patients from 23 provinces in China.Phenotypic profiles showed that the primary diagnosis included steroid-resistant nephrotic syndrome(SRNS,23.5%),glomerulonephritis(GN,32.2%),congenital anomalies of the kidney and urinary tract(CAKUT,21.2%),cystic renal disease(3.9%),renal calcinosis/stone(3.6%),tubulopathy(9.7%),and chronic kidney disease of unknown etiology(CKDu,5.8%).The pathogenic variants of 105 monogenetic disorders were identified.Ten distinct genomic disorders were identified as pathogenic copy number variants(CNVs)in 11 patients.The diagnostic yield differed by subgroups,and was highest in those with cystic renal disease(66.3%),followed by tubulopathy(58.4%),GN(57.7%),CKDu(43.5%),SRNS(29.2%),renal calcinosis/stone(29.3%)and CAKUT(8.6%).Reverse phenotyping permitted correct identification in 40 cases with clinical reassessment and unexpected genetic conditions.We present the results of the largest cohort of children with kidney disease in China where diagnostic exome sequencing was performed.Our data demonstrate the utility of family-based exome sequencing,and indicate that the combined analysis of genotype and phenotype based on the national patient registry is pivotal to the genetic diagnosis of kidney disease.