Impulsiveness mediates the association between GABRA2 SNPs and lifetime alcohol problems

• Published in: Genes, brain and behavior Vol. 12; no. 5; pp. 525 - 531
• Main Authors: Villafuerte, S., Strumba, V., Stoltenberg, S. F., Zucker, R. A., Burmeister, M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-07-2013; Blackwell; John Wiley & Sons, Inc
• Subjects: Addictive behaviors; Adult; Adult and adolescent clinical studies; Alcohol problems; Alcohol use; Alcoholism; Alcoholism - genetics; Alcoholism and acute alcohol poisoning; Biological and medical sciences; Female; GABRA2; Genetic Association Studies; Humans; Impulsive Behavior - genetics; impulsiveness; Introns; Male; mediation; Medical sciences; Middle Aged; Polymorphism; Polymorphism, Single Nucleotide; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Receptors, GABA-A - genetics; single‐nucleotide polymorphisms; Toxicology; Human; GABRA2; Impulsivity; Alcoholism; Genetic variant; Genetic determinism; impulsiveness; Gene; Genetics; Single nucleotide polymorphism; mediation; single-nucleotide polymorphisms; Alcohol problems
• ISSN: 1601-1848; 1601-183X
• DOI: 10.1111/gbb.12039

Genetic variants in GABRA2 have previously been shown to be associated with alcohol measures, electroencephalography (EEG) β waves and impulsiveness‐related traits. Impulsiveness is a behavioral risk factor for alcohol and other substance abuse. Here, we tested association between 11 variants in GABRA2 with NEO‐impulsiveness and problem drinking. Our sample of 295 unrelated adult subjects was from a community of families with at least one male with DSM‐IV alcohol use diagnosis, and from a socioeconomically comparable control group. Ten GABRA2 SNPs (single‐nucleotide polymorphisms) were associated with the NEO‐impulsiveness (P < 0.03). The alleles associated with higher impulsiveness correspond to the minor alleles identified in previous alcohol dependence studies. All ten SNPs are in linkage disequilibrium (LD) with each other and represent one effect on impulsiveness. Four SNPs and the corresponding haplotype from intron 3 to intron 4 were also associated with Lifetime Alcohol Problems Score (LAPS, P < 0.03) (not corrected for multiple testing). Impulsiveness partially mediates (22.6% average) this relation between GABRA2 and LAPS. Our results suggest that GABRA2 variation in the region between introns 3 and 4 is associated with impulsiveness and this effect partially influences the development of alcohol problems, but a direct effect of GABRA2 on problem drinking remains. A potential functional SNP rs279827, located next to a splice site, is located in the most significant region for both impulsiveness and LAPS. The high degree of LD among nine of these SNPs and the conditional analyses we have performed suggest that all variants represent one signal.
GABRA2 SNPs are associated with NEO‐impulsiveness and Lifetime Alcohol Problems (LAPS). Impulsiveness partially mediates the association of GABRA2 SNPs with LAPS.