Dopamine D2 receptor polymorphisms and susceptibility to alcohol dependence in Indian males: a preliminary study

<p>Abstract</p> <p>Background</p> <p>Dopamine is an important neurotransmitter involved in reward mechanism in the brain and thereby influences development and relapse of alcohol dependence. The dopamine D2 receptor (<it>DRD2</it>) gene on chromosome 11 (q22-q23) has been found to be associated with increased alcohol consumption through mechanisms involving incentive salience attributions and craving in alcoholic patients. Therefore, we investigated the association of three single nucleotide polymorphisms (SNP) in <it>DRD2 </it>gene with alcohol dependence in the north Indian subjects.</p> <p>Methods</p> <p>In a retrospective analysis, genetic association of three polymorphisms from <it>DRD2 </it>gene with alcohol dependence was investigated using a case-control approach. Alcohol dependence was determined by DSM-IV criteria and a total of 90 alcoholics and 60 healthy unrelated age-matched control subjects were recruited. Odds ratio and confidence interval was calculated to determine risk conferred by a predisposing allele/genotype/haplotype. Logistic regression analysis was carried out to correlate various clinical parameters with genotypes, and to study pair-wise interactions between SNPs.</p> <p>Results</p> <p>The study showed a significant association of -141C Ins allele and a trend of association of TaqI A1 allele of <it>DRD2 </it>with alcohol dependence. Haplotype with the predisposing -141C Ins and TaqI A1 alleles (-141C Ins-A-A1) seems to confer ≈ 2.5 times more risk to develop alcohol dependence.</p> <p>Conclusions</p> <p>The study provides preliminary insight into genetic risk to alcohol dependence in Indian males. Two polymorphisms namely, -141C Ins/Del and TaqI A in <it>DRD2 </it>gene may have clinical implications among Indian alcoholic subjects.</p

Association of <it>ADHIB </it>and <it>ALDH2 </it>gene polymorphisms with alcohol dependence: A pilot study from India

Abstract Functional polymorphism in the genes encoding alcohol dehydrogenase (ADH) 1B and aldehyde dehydrogenase (ALDH) 2 are considered most important among several genetic determinants of alcohol dependence, a complex disorder. There is no report on the widely studied Arg47His and Glu487Lys polymorphisms from Indian alcoholdependent populations. In this paper, we report, for the first time, allelic and genotypic frequencies of Arg47His and Glu487Lys single nucleotide polymorphisms (SNPs) in North Indian alcohol-dependent subjects. A total of 174 alcohol-dependent males, recruited using DSM IV criteria (American Psychiatric Association, 1994), were genotyped using the polymerase chain reaction-restriction fragment length polymorphism method. The results obtained from genetic analysis were correlated with clinical parameters using Student's t-test or Mann Whitney's U test. The highlight of the study findings was the uniquely high frequency of the ALDH2*2/*2 genotype (among alcohol-dependent subjects) being a risk-conferring factor for alcohol dependence.</p