Analysis of single nucleotide polymorphisms and haplotypes in the neuropeptide Y gene: No evidence for association with alcoholism in a German population sample

Background: Several lines of evidence from animal and electrophysiological studies indicate that the neuropeptide Y (NPY) gene is involved in the pathophysiology of alcohol dependence. Recent studies have provided evidence for an association between a Leu7Pro polymorphism, as well as 2 promoter single nucleotide polymorphisms (SNPs) in the NPY gene (G-602T, T-399C) and alcohol dependence. The aim of the present study was to analyze these variants in a large sample of the Munich Gene Bank of Alcoholism. Methods: We performed single SNP and haplotype studies in 465 alcohol dependent patients and 448 healthy controls with 3 SNPs in the promoter region (-883ins/del, G-602T, T-399C) and the Leu7Pro polymorphism in exon 2 of the NPY gene. Results: Neither single SNP-, nor haplotype analysis could detect significant associations with alcohol dependence. Additionally we could not detect any relation to Cloninger's Type 1/2 or Babor's Type A/B classification, to withdrawal symptoms, to the age of onset or to the amount of alcohol intake. Conclusions: In conclusion, our results suggest that the analyzed SNPs, as well as the corresponding haplotypes of the NPY gene are unlikely to play a major role in the pathophysiology of alcohol dependence in the investigated sample from the German population. Further analyses are needed to confirm the present results.