Dopamine receptor gene polymorphisms in Guangzhou Hans

Objective: To determine the distribution of dopamine D2, D3, and D5 receptor (DRD2, DRD3, DRD5) gene polymorphisms in Guangzhou Hans. Methods: A total of 141 healthy Guangzhou Hans were studied by the use of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR-amplification of specific allele (PASA) techniques. Current results were compared with the data on other ethnic groups. Results: Within the 141 individuals tested, the frequencies of the A1 (Taq I -) and A2 (Taq I +) alleles of the Taq I A mutation site in the 3' non-coding region of the DRD2 gene were found to be 48% and 52%, respectively. The observed frequencies of the A1A1, A1A2 and A2A2 genotypes were found to be 17%, 52% and 31%, respectively, which met Hardy-Weinberg equilibrium. The frequencies of the A1 and A2 alleles of the Bal I mutation site in the exon 1 of DRD3 gene were found to be 73% and 27%, respectively. The observed frequencies of the A1A1, A1A2 and A2A2 genotypes were found to be 53%, 39% and 8%, respectively, which met Hardy-Weinberg equilibrium. The frequencies of the 1 and 2 alleles of the Msp I mutation site in the intron 5 of DRD3 gene were found to be 62.5% and 37.5%, respectively. The observed frequencies of the 1-1, 1-2 and 2-2 genotypes were found to be 35%, 55% and 10%, respectively, which met Hardy-Weinberg equilibrium. No linkage disequilibrium was observed between the Bal I and Msp I polymorphism in Guangzhou Hans (χ² = 0.165,P>0.05). The frequencies of the T and C alleles of the T978C mutation site of DRD5 gene were found to be 51% and 49%, respectively. The observed frequencies of the T/T, T/C and C/C genotypes were found to be 23.6%, 54.6% and 21.8%, respectively, which met Hardy-Weinberg equilibrium. Conclusion: The polymorphisms of DRD2, DRD3, DRD5 gene in Guangzhou Hans were high and different from those in other populations.