HCN1 and epilepsy: We performed stratified analysis of age in the TLE group and observed that the methylation levels of seven epilepsy-related ion channel genes, namely, GABRB1, GABRB2, GABRB3, GRIN1, GRIN2A, HCN1, and KCNB1, were relatively low in the young subgroup; this indicates that the methylation of most of the genes tested increases with age in TLE.