GJB2 and hearing loss disorder: A total of 104 patients (30.68%) were confirmed to be associated with hereditary hearing loss caused by GJB2 mutation: 49 homozygotes (42 with the c.235delC allele, 4 with c.299_300delAT, and 3 with the c.109G>A allele) and 55 compound heterozygotes.