GJB2 and nonsyndromic deafness: As for genetic factors of nonsyndromic deafness in China, the average value of variant in GJB2 seems to be the most common (23.37%), followed by SLC26A4 (14.74%), mtDNA 12SrRNA A1555G ( 2.44%), GJB3 (1.97%) and GJB6 (1.33%) genes.