RESUMO
We report on the frequency of DRD2A1, DRD3A1, DRD4/2R-10R, and 5HT2CA1 variants in the population of the city of La Plata (Argentina) and in Amerindians from Argentina, Paraguay, and Chile. In the Amerindian sample, the prevalence of DRD2A1 and DRD4/4R variants were, respectively, significantly lower and significantly higher than frequencies reported in other Native Americans. Comparison of average allele and genotype frequencies between La Plata and Amerindians showed significant differences for 5HT2CA1 and DRD4. As La Plata is a population with predominant European and Amerindian components, we used mtDNA and Y-specific markers to subdivide the La Plata sample into two strata: Amerindian La Plata and non-Amerindian La Plata. Significant variations between the two strata were detected for DRD2A1, DRD3A1, and DRD4/4R allele frequencies, and for the homozygous DRD4/4R/4R genotype. Several controversial reports suggest a possible association between a variant of DRD and/or 5HT2C receptor genes and the clinical expression of several psychiatric disorders. We suggest that ethnic variations in the prevalence of the allelic forms of these genes may be a confounding factor to be taken into consideration in studies of association between dopaminergic and serotonergic receptor genotypes and neuropsychiatric and mood disorders.
