Genomic influences on alcohol problems in a population-based sample of young adults

AimsAlcohol problems (AP) contribute substantially to the global disease burden. Twin and family studies suggest that AP are genetically influenced, although few studies have identified variants or genes that are robustly associated with risk. This study identifies genetic and genomic influences on AP during young adulthood, which is often when drinking habits are established. DesignWe conducted a genome-wide association study of AP. We further conducted gene-based tests, gene ontology analyses and functional genomic enrichment analyses to assess genomic factors beyond single variants that are relevant to AP. SettingThe Avon Longitudinal Study of Parents and Children, a large population-based study of a UK birth cohort. ParticipantsGenetic and phenotypical data were available for 4304 participants. MeasurementsThe AP phenotype was a factor score derived from items from the Alcohol Use Disorders Identification Test, symptoms of DSM-IV alcohol dependence, and three additional problem-related items. FindingsOne variant met genome-wide significance criteria. Four out of 22880 genes subjected to gene-based analyses survived a stringent significance threshold (q<0.05); none of these have been implicated previously in alcohol-related phenotypes. Several biologically plausible gene ontologies were statistically over-represented among implicated single nucleotide polymorphisms (SNPs). SNPs on the Illumina 550K SNP chip accounted for similar to 5% of the phenotypical variance in AP. ConclusionsGenetic and genomic factors appear to play a role in alcohol problems in young adults. Genes involved in nervous system-related processes, such as signal transduction and neurogenesis, potentially contribute to liability to alcohol problems, as do genes expressed in non-brain tissues.