Elevated SLC26A4 gene promoter methylation is associated with the risk of presbycusis in men.

Presbycusis affects approximately one-third of people over the age of 65 and is a worldwide health problem. In the current study, whether the methylation level of solute carrier family 26 member 4 (SLC26A4) predicted an increased risk of presbycusis was investigated. Peripheral blood samples from 102 patients with presbycusis and 104 controls were collected, and the methylation of the CpG sites of SLC26A4 was measured by applying pyrosequencing technology combined with sodium bisulfate DNA conversion chemistry. Within the SLC26A4 promoter region, one CpG site (CpG3) exhibited a significantly (P<0.0001) greater methylation level in the patients with presbycusis (26.5±5.56%) compared with the controls (23.8±3.85%). Significantly different CpG3 methylation levels were observed between the patients with presbycusis and the controls among the male participants (P=0.0004). In addition, a significant decrease in the transcriptional level of SLC26A4 in peripheral blood was observed in the patients with presbycusis compared with the controls. Furthermore, analyses of the receiver operating characteristic (ROC) curves indicated that CpG3 methylation at the SLC26A4 promoter predicted the risk of presbycusis in the male participants (AUC=0.684, 95% CI=0.584‑0.784, P=0.001). The results demonstrated the significance of the CpG site methylation level of SLC26A4, and thus provides a potential marker for the diagnosis of presbycusis.