Overall, some of the above studies have demonstrated significant associations between DNA methylation and AUDs or AUD-related phenotypes, although inconsistent results have also been reported. These studies have significant limitations: (i) only a small proportion of CpG sites in the genome have been examined for their associations with AUDs (eg, the Illumina Infinium HumanMethylation450 BeadChip probes can only cover about 1.7% of CpGs in the human genome); (ii) few studies have examined AUD-associated DNA methylation changes in reward-related brain regions; and (iii) most importantly, very few studies have explored whether AUD-associated DNA methylation changes are inherited or resulted from chronic alcohol drinking. These issues are addressed below.
