A novel deletion-frameshift mutation in the S1 region of HERG gene in a Chinese family with long QT syndrome

摘要

Background The congenital Long QT syndrome (LQTS) is a hereditary cardiac channelopathy that is characterized by a prolonged QT interval,syncope,ventricular arrhythmias,and sudden death.The chromosome 7-linked type 2 congenital LQTS (LQT2) is caused by gene mutations in the human ether-a-go-go-related gene (HERG).Methods A Chinese family diagnosed with LQTS were screened for KCNQ1,HERG and SCN5A,using polymerase chain reaction (PCR),direct sequencing,and clong sequencing.We also investigated the mRNA expression of the HERG gene.Results We identified a novel i414fs+98X mutation in the HERG gene.The deletion mutation of 14-bp in the first transmembrane segment (S1) introduced premature termination codons (PTCs) at the end of exon 6.This mutation would result in a serious phenotype if the truncated proteins co-assembled with normal subunit to form the defective channels.But only the proband was symptomatic.Conclusions We found that the mRNA level of the HERG gene was significantly lower in 1414fs+98X carriers than in noncarriers.We found a novel 1414fs+98X mutation.The mRNA level supports that NMD mechanism might regulate the novel mutation.