SU117 - NEW AND META-ANALYTIC GENOME-WIDE STUDIES OF HEAVY ALCOHOL CONSUMPTION WITH REDUCTION TO A CLINICALLY TRANSLATABLE DIGITAL PCR ASSAY

Abstract

Background The detection and quantification of heavy alcohol consumption is a challenge for researchers and clinicians alike. Unfortunately, its quantification and treatment are stymied by the lack of clinically employable biomarkers. In 2014, using the Illumina 450K platform, we published a preliminary DNA methylation signature of heavy alcohol consumption in otherwise healthy individuals that remits as a function of abstinence. Herein, we present new genome wide methylation findings and a meta-analysis of all results. Methods Heavy alcohol consuming subjects were ascertained through local treatment centers using protocols and procedures approved by the Western IRB. After written consent, subjects were interviewed with a version of the Semi-Structured Assessment for the Genetics of Alcoholism and a series of instruments designed to assess alcohol consumption. Blood specimens were processed to provide DNA as previously described while serum was tested using AbNova ELISA kits to determine tobacco and cannabis consumption status.Genome-wide DNA methylation from peripheral blood DNA was assessed using Illumina Epic and 450K arrays. The resulting array data was processed and cleaned via standard published procedures. The resulting clinical methylation data was analyzed using MethLAB and JMP as indicated. Droplet digital PCR was performed using instruments and reagents from BioRad and a series of custom designed assays. Bisulfite conversion of DNA was conducted using materials from Qiagen. Methylation status was them determined using proprietary Bio Rad software. Results Using the new Epic methylation array and DNA from consecutive heavy drinkers, we replicate the 2014 results and show that 17429 CpG residues are differentially methylated in heavy drinkers. Meta-analysis of all data from the 448,059 probes common to both Illumina platforms show a similarly profound signature with confirmation of findings from other groups. Principal components analyses show that genome-wide methylation changes in response to alcohol consumption load on two major factors with one component accounting for over 60% of the variance. We additionally show that a five marker panel of methylation probes accurately classifies use status with an AUC of 0.97. Finally, using droplet digital PCR, we convert these array-based findings to clinically translatable assay and show that they accurately assess alcohol use status in third independent cohort. Discussion We conclude that DNA methylation assessments are capable of quantifying alcohol use status and suggest that that these epigenetic approaches will find widespread use in both clinical research and patient care.