Genetic Variants in the Fat Mass- and Obesity-Associated (FTO) Gene are Associated with Alcohol Dependence

Variants (such as rs9939609) in the fat mass- and obesity-associated (FTO) gene have been associated with obesity, type 2 diabetes, some cancers, and alcohol consumption. This study tested the associations of 167 single-nucleotide polymorphisms (SNPs) within FTO gene with alcohol dependence (AD) using two Caucasian samples: the Collaborative Study on the Genetics of Alcoholism (COGA) sample (660 AD cases and 400 controls) and the Study of Addiction: Genetics and Environment (SAGE) sample (623 cases and 1,016 controls). Logistic regression analysis of AD as a binary trait was performed using the PLINK software. For the SAGE sample, the top three SNPs showing associations with AD were rs8062891, rs1108086, and rs1420318 (p = 0.00088, 0.00086 and 0.00086, respectively). Two SNPs (rs12597786 and rs7204609) associated with AD in the SAGE sample (p = 0.017 and 0.034, respectively) were replicated in the COGA sample (p = 0.017 and 0.014, respectively). Through meta-analysis of two samples using PLINK, the top three SNPs associated with AD were rs8062891, rs12597786, and rs7204609 (p = 0.00064, 0.00076 and 0.0011, respectively). Haplotype analysis in the SAGE sample further supported the associations with AD in single-marker analysis. In addition, we found association of rs17817449 (which has a strong linkage disequilibrium with rs9939609) with AD in the SAGE sample (p = 0.00339). The findings provide evidence of joint intervention and prevention of AD and obesity.