Polymorphisms in the N-methyl-D-aspartate receptor 1 and 2B subunits are associated with alcoholism-related traits

Background This study examined the hypothesis that allelic variants of the ionotropic glutamatergic N-methyl-D-aspartate receptor (NMDAR) are associated with vulnerability to alcoholism and some related traits. Methods We investigated the silent G2108A and C2664T polymorphisms of the NMDAR1 and the NMDAR2B genes, respectively. The case control study included 367 alcoholic and 335 control subjects of German origin. The family-based study comprised 81 Polish alcoholic patients and their parents using the transmission disequilibrium test. Results The genotype frequencies of the NMDAR1 polymorphism differed significantly between control and alcoholic subjects. This difference was also observed in more homogenous subgroups of alcoholic subjects with vegetative withdrawal syndrome and Cloninger type 1. Patients with a history of delirium tremens or seizures during withdrawal showed a significantly increased prevalence of the A allele. Genotyping of the NMDAR2B polymorphism revealed a significantly reduced T allele in Cloninger type 2 alcoholics and in patients reporting an early onset compared with control subjects. Our family-based study for NMDAR2B, revealed a trend to a preferred transmission of the C allele by the fathers, and families with early-onset patients contributed most to this trend. Conclusions These results suggest that variants in NMDAR genes are associated with alcoholism and related traits.