High mutation rate of NPHP3 in 18 Chinese infantile nephronophthisis patients

The present study was designed to explore mutations of NPHP2 and NPHP3 and clinical features in 18 Chinese infantile nephronophthisis (NPHP) patients.Patients were subjected to screen for mutations in both NPHP2 and NPHP3, and clinical data were collected.Eighteen patients from 17 families were included in this study. Eight of 17 (47.1%) patients detected were identified to have mutations in NPHP3, but none had a mutation in NPHP2. Of the patients with NPHP3 mutations, four had compound heterozygous mutations, and the other four harboured single heterozygous mutations. Ten of the NPHP3 mutations were novel. Low molecular weight proteinuria was observed in all 16 detected patients. Renal histology were available in seven children, five patients showed infantile type NPHP features, and the other two patients from the same family showed juvenile type NPHP features. Liver involvement was observed in all patients with NPHP3 mutations and congenital heart disease in two patients harbouring NPHP3 mutation of c.2369 T > C (p.L790P).In this group of infantile NPHP patients, mutations of NPHP3 were prevalent, whereas mutation of NPHP2 was absent. Genotype to phenotype correlations were observed in patients with NPHP3 mutations and all patients with NPHP3 mutations showed renal-hepatic phenotype.