D2 DOPAMINE RECEPTOR TaqI ALLELES IN MEDICALLY ILL ALCOHOLIC AND NONALCOHOLIC PATIENTS

The prevalence of TaqI A alleles of the D₂ dopamine receptor(DRD2) gene was examined in two subgroups of medically ill nonalcoholics(more prevalent and less prevalent substance users, MPSU andLPSU, respectively) and in two subgroups of medically ill alcoholics(more severe and less severe alcoholics, MSA and LSA, respectively).The prevalence of the Al allele in the 80 nonalcoholic and 73alcoholic patients was 30.0% and 52.1%, respectively (P = 0.009).In the four subgroups of these patients, the prevalence of thisallele was: LPSU = 18.2%, MPSU = 34.5%, LSA = 44.4% and MSA= 58.3%. Linear trend analysis showed that as the use of substancesand severity of alcoholism increase, so does Al prevalence (P= 0.001). Specific, subgroup comparisons showed Al prevalencein MSA to be about 3-fold (P = 0.007) and 1.5-fold (P = 0.04)higher than in LPSU and MPSU subgroups, respectively. Similarly,in a combined analysis of independent studies, Al prevalencein MSA was higher when compared to LSA (P < 5 x 10^–3),MPSU (P < l0^–4 and LPSU (P < l0^–8) subgroups.There was virtually no difference in the prevalence of the Alallele between LSA and MPSU subgroups. None of the specificmedical or neuropsychiatric complications of alcoholism wasassociated with the Al allele. In conclusion, the severity ofalcohol dependence in alcoholics and of substance use behaviorsin controls are important variables in DRD2 allelic association.The present report and converging lines of evidence suggestthat the DRD2 locus could represent a prominent gene risk factorfor susceptibility to severe alcoholism. However, other genesand environmental factors, when combined, still play the largerrole.     

中国北方老年人多巴胺受体D2基因多态性与吸烟的相关性研究

目的:探讨多巴胺受体D2(DRD2)基因多态性在中国北方社区老年人群中的分布及其与吸烟的关系。方法:调查392名中国北方社区老年人的吸烟史,包括吸烟起始年龄、年吸烟量(包/年)、吸烟持续年限。酚提取法提取研究对象的基因组DNA,用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)分析方法,检测DRD2基因TaqⅠA和TaqⅠB多态频率。统计分析DRD2基因多态与吸烟的相关性。结果:在本人群中,65.8%的男性吸烟,27.2%的女性吸烟。DRD2 TaqⅠA1和TaqⅠA2等位基因频率分别为39.7%和60.3%,DRD2 TaqⅠB1和TaqⅠB2等位基因频率分别为43.2%和56.8%。DRD2基因多态与吸烟与否、吸烟年限和年吸烟量无明显相关。然而,在吸烟起始年龄≥30岁的吸烟者中,A1和B1等位基因频率分别为51.0%和55.2%,高于吸烟起始年龄<30岁的吸烟者38.5%和41.0%(P=0.017和0.018)。结论:中国北方老年人男性吸烟者多。DRD2 TaqⅠA1、B1等位基因可能是中国北方老年人吸烟的相关基因,与吸烟起始年龄有关。但尚需更大样本量的独立研究加以证实。