Objective: To screen the mutation of the beta and gamma subunits of epithelial sodium channel gene SCNN1 in two families with Liddle's syndrome.
Methods: Two patients clinically diagnosed as Liddle's syndrome and their family members were enrolled. Peripheral blood samples were collected and total genomic DNA was prepared. Polymerase chain reaction (PCR) was used to amplify the exon 13 of the SCNN1B and SCNN1G gene. PCR products were purified and subjected to direct DNA sequencing.
Results: A heterozygous nonsense mutation at codon 564 of the SCNN1B gene from CGA(Arg) to stop codon(TGA) was detector in the proband of family 1. More importantly, a novel heterozygous nonsense mutation of CAG(Gln) to stop codon TAG at codon 567 of the SCNN1G gene was detected in the proband and another two members of family 2.
Conclusion: Screening for specific mutations of the SCNN1 gene in relatives of patients with Liddle's syndrome can be used to identify the previously unrecognized cases within the family. A new nonsense mutation(Q567X) of the SCNN1G gene is likely the cause of Liddle's syndrome in family 2.