Two published studies applied the Illumina Infinium HumanMethylation27 BeadChip assay to identify genes that were differentially methylated in AUD subjects.72,73 One study compared genome-wide blood DNA methylation differences between 63 male AUD patients and 65 male controls, and revealed differential methylation in a number of genes (including the alcohol dehydrogenases 1A gene [ADH1A], the alcohol dehydrogenases 7 gene [ADH7], the aldehyde dehydrogenase 3B2 gene [ALDH3B2], and the cytochrome P450 2A13 gene [CYP2A13]) that are involved in stress, immune response, signal transduction, and metabolism.72 Another study used the same DNA methylation platform to examine DNA methylomic profiles in the saliva of 309 hazardous drinkers, and identified multiple CpGs sites (including those sites near the aldehyde dehydrogenase 1 family, member A2 gene [ALDH1A2]) that were associated with loss of control over drinking.73
