[Sequencing analysis of whole SLC26A4 gene in severe to profound sensorineural hearing loss patients with IVS7-2A to G mutation of the gene].

OBJECTIVE

To investigate the whole sequence of the SLC26A4 gene in moderate to profound sensorineural hearing loss (SNHL) patients with IVS7-2A to G mutation of the gene in China.

METHODS

Whole SLC26A4 gene sequence was analyzed by direct sequencing in 80 SLC26A4 gene IVS7-2A to G mutation carriers for the occurrence of a second mutation in the gene.

RESULTS

Forty-seven out of the 80 patients were found to have a second heterozygous mutation, whereas a single IVS7-2A to G mutation could be responsible for SNHL in the remaining 33 patients. Three novel mutations, 5+ 2T to A, 14-2A to G and 1825del G, were identified. The five most common mutations include H723R (20%), T410M(5%), C.1705+ 5G to A (15+ 5G to A)(5%), L676Q(5%), and N392Y (3.75%). Exon 17 harbored the most types of compound heterozygosity with the IVS7-2A to G mutation.

CONCLUSION

A Chinese specific SLC26A4 diversity was found, and comparable SLC26A4 contributing to deafness. This study suggested that if a heterozygous SLC26A4 mutation is found in a patient with deafness, other exons of the SLC26A4 gene should be analyzed. Furthermore, double heterozygosity of the SLC26A4 gene may also account for some of the disease phenotype.