APOE and presbycusis: The potassium voltage-gated channel member 4 gene (KCNQ4,OMIM ID:603537) [16]; N-acetyltransferases (NAT2*6A,OMIM ID:612182) [17-19]; the grainyhead-like 2 gene (GRHL2 ,OMIM ID: 608576) [20]; the apolipoprotein E gene (APOE ε4 OMIM ID: 107741) [21]; the endothelin-1 gene (EDN1, OMIM ID: 131240) [22,23]; the uncoupling protein gene (UCP2, OMIM ID: 601693) [24] and the mitochondrial DNA (mtDNA) 4977 common deletion [25,26] have all been reported to be correlated with ARHI.