Mutations in NPHS2 in sporadic steroid-resistant nephrotic syndrome in Chinese children

Since the identification of the NPHS2 gene, various investigators have demonstrated that an NPHS2 mutation is a frequent cause of sporadic steroid-resistant nephrotic syndrome (SRNS), and occurs in 10.5-28% of children with the syndrome. Idiopathic nephrotic syndrome (INS) is also the most frequent glomerular disease in Chinese children, of which approximately 20% of cases show steroid resistance. To our knowledge, however, whether or not NPHS2 is the causative gene in Chinese sporadic SRNS has not been established. This study aims to examine mutations in NPHS2 in Chinese children with sporadic SRNS.

We examined 23 Chinese children with sporadic SRNS for mutations in NPHS2. The mutational analysis of NPHS2 was performed by polymerase chain reaction, denaturing high-performance liquid chromatography and DNA sequencing.

A heterozygous missense mutation of L361P in exon 8 of NPHS2 was detected in one of 23 children with sporadic SRNS, whereas it was not found in 53 controls. We also identified seven NPHS2 polymorphisms, -51G>T, 288C>T, IVS3-46C>T, IVS3-21C>T, IVS7-74G>C, 954T>C and 1038A>G, in some patients and controls. There was no significant difference in the genotypic and allelic frequencies of these polymorphisms between the patients and controls.

The results demonstrate that NPHS2 mutations are also present in Chinese sporadic SRNS. Our investigation supports the necessity of searching for mutations in NPHS2 in Chinese children with sporadic SRNS.