These studies identified significant variation in DNA methylation within gene promoter regions including DUSP4, C21orf58, ALG10, C3, LCK, GBX2. However, female-only studies highlighted a different subset of genes to be significantly differentially methylated, namely, TCF25, FGFR1, POLE, P2RX2, KCNQ5, ERBB3 and SOCS3. One study reported the significant differential methylation was detected in genes that were related to the concurrent disease, Type 2 Diabetes Mellitus, with no hearing loss genes being affected [11]. The gene discussed is TCF25; the disease is type 2 diabetes mellitus.