SLC26A4 and hearing loss disorder: Interestingly, these two biallelic mutations in SLC26A4 shared one common mutant allele (IVS7-2A>G) and the same codon of the other mutant allele (p.H723D, p.H723R), but led to different changes of amino acid and both resulted in the deafness phenotype, which indicated that codon 723 in SLC26A4 could be a hot-region responsible for the development of hearing loss.