Many studies of deafness molecular epidemiology in China have shown that a number of non-syndromic hearing loss (NSHL) genes are caused by only several mutated genes, such as the gap junction protein beta-2 gene (GJB2 gene), beta-3 gene (GJB3 gene), and SLC26A4 gene (PDS gene), and mitochondrial DNA (mtDNA).[8] Hearing loss gene identification has effectively improved the clinical diagnosis and management of deaf and hard-of-hearing people.[9]. The gene discussed is GJB2; the disease is hearing loss disorder.