Association of microRNA biogenesis pathway gene variants and alcohol dependence risk

Alcohol dependence (AD) is a neuropsychiatric disorder to which both genetic and environmental factors contribute. Especially, multiple genetic factors are promising to explain the etiology of AD. microRNAs (miRNAs) are members of a family of noncoding small RNAs, which are thought to be responsible for the altered gene expression in neuropsychiatric disorders. We hypothesized that single nucleotide polymorphisms (SNPs) in the miRNA biogenesis pathway may result in dysregulation of miRNA levels inside the cell. The aim of this study was to test an association between miRNA biogenesis gene variants and AD risk. Real-time polymerase chain reaction genotyping experiment was conducted on DNA samples from 123 alcohol-dependent patients and 135 healthy controls. We found that AGO1 rs595961 (χ(2) = 9.066, p = 0.003; odds ratio [OR] = 0.459, 95% confidence interval [CI]: 0.275-0.768) and AGO2 rs4961280 (χ(2) = 4.111, p = 0.043; OR = 0.590, 95% CI: 0.353-0.986) G alleles have significantly altered the risk for AD, and also there is a significant association of GEMIN4 rs910924 (χ(2) = 5.291, p = 0.021; OR = 1.913, 95% CI: 1.094-3.344) T allele with the risk for AD. We also found statistically significant difference in AGO1 rs595961 (χ(2) = 11.139, p = 0.001) and DGCR8 rs1640299 (χ(2) = 13.001, p = 0.002) genotype frequencies between case-control groups. This is the first study to investigate the effects of SNPs in the miRNA biogenesis pathway on AD risk. In conclusion, we identified a significant association of miRNA biogenesis genes with altered AD risk, and these results could be a guide to research on the role of miRNAs in AD in the future.