Alcohol use disorder (AUD) contributes significantly to the global burden of disease. The susceptibility for AUD is mediated through an interaction of genetic risk factors and environmental influences. These gene × environment (G × E) interactions manifest as epigenetic regulations of gene expression, among other things. Previous research suggests an association between Ganglioside Induced Differentiation Associated Protein 1 (GDAP1) DNA methylation and AUD. Here, we investigate the epigenetic dysregulation of GDAP1 in AUD through comparing DNA methylation in whole blood and saliva, as well as H3K4-trimethylation (H3K4me3) in PBMC (Peripheral Blood Mononuclear Cell) samples of AUD patients and healthy control individuals. Additionally, the effect of abstinence-based therapy was investigated. AUD patients before treatment exhibit significantly lower promoter DNA methylation levels in whole blood and saliva, as well as lower H3K4me3 near the transcription start site. GDAP1 gene expression was not significantly altered. Following treatment, H3K4me3 was significantly increased in patients and no longer differed from control individuals. There was no significant effect of treatment on DNA methylation. We conclude that GDAP1 is epigenetically dysregulated in AUD patients, and is responsive to abstinence-based therapy at the level of H3K4me3. It should be investigated further to establish its potential as a diagnostic biomarker.
Keywords: DNA-methylation; GDAP1; H3K4me3; alcohol use disorder; epigenetics; gene expression.