Philibert et al. performed two EWAS studies on AUDs using the Illumina Infinium HumanMethylation450 BeadChip.37,39 Initially, they examined the impact of recent alcohol use on DNA methylomes using lymphoblast DNAs derived from 165 female adoptees, and found widespread changes in DNA methylation across the genome due to recent alcohol consumption.37 In a follow-up study with 33 AUD patients and 33 controls, they also observed widespread DNA methylation changes in the peripheral blood of AUD subjects, and these changes were mapped to gene networks involved in apoptosis.39 The most significant findings were generated from CpG sites in the promoter region of GDAP1, and the hypomethylation of GDAP1 in alcohol dependent patients was validated by a recent study.59 However, no gene was found to be differentially methylated at the genome-wide level when comparing AUD patients’ methylomes at the beginning of treatment and after 4 weeks of treatment. Additionally, Zhao et al. compared peripheral blood DNA methylome patterns between 10 AUD subjects and 10 paired siblings (without AUDs).38 They identified 865 hypomethylated and 716 hypermethylated CpG sites in peripheral blood DNAs of AUD
