GJB2 and sensorineural hearing loss disorder: In particular, GJB2 (OMIM: 121011), GJB3 (OMIM: 603324), SLC26A4 (OMIM: 605646), and the mitochondrial gene MT-RNR1 (OMIM: 561000) are the 4 major causative genes of hereditary nonsyndromic SNHL in China [7].