Background: Congenital nephrotic syndrome (CNS) of the Finnish type is a rare autosomal-recessive disorder. Kestila et al reported that a positionally cloned gene for a novel glomerular protein nephrin is mutated in CNS. Most Finnish patients have one of two mutations. In this study, we described a Japanese CNS family associated with a novel missense point mutation in the nephrin gene.
Methods: Reverse transcription-polymerase chain reaction, polymerase chain reaction, and sequence analysis were used.
Results: The patient had the three missense mutations homozygously. One mutation was already reported as sequence variant. The two other novel mutations were the GAG to AAG transition, leading to a Glu447Lys and the GAC to GTC transition, predicting an Asp819Val substitution in the nephrin protein.
Conclusion: Our findings indicate that an abnormality of nephrin may cause CNS of the Finnish type in Japanese subjects.