Worldwide ethnic distribution of the G protein beta 3 subunit 825T allele and its association with obesity in Caucasian, Chinese, and Black African individuals

Recently, it was demonstrated that one allele (825T) of the gene encoding t he G protein beta 3 subunit (GNB3) is associated with hypertension in Germa ns. This study investigates a possible association with obesity in young ma le Germans, Chinese, and black South Africans with low, intermediate, and h igh 825T allele frequencies, respectively. In each of these three distinct cohorts, the 825T allele frequency was increased significantly in overweigh t (body mass index [BMT] greater than or equal to 25 kg/m(2)) and obese ind ividuals (BMI >27 kg/m(2)) compared to those with normal weight. The 825T a llele frequencies in these three BMI groups were, respectively, 29.5, 39.3, and 47.7% in Germans, 46.8, 53.9, and 58.6% in Chinese, and 83.1, 87.7, an d 90.9% in South Africans. In each of these three distinct groups, the 825T allele was significantly associated with obesity with odds ratios between 2 and 3. More urban than rural black Africans were overweight despite simil ar 825T allele frequencies in both populations, which underscores the role of both genetic and environmental factors. BP values in young male whites i ncreased significantly with increasing BMI values but were independent of t he C825T polymorphism, suggesting that hypertension associated with the 825 T allele could be a consequence of obesity. Genotyping of 5254 individuals from 55 native population samples from Africa, the Americas, Europe, Asia, Australia, and New Guinea demonstrated highest 825T allele frequencies in b lack Africans (82%) and intermediate values in east Asians (47%). It is ant icipated that high frequencies of the 825T allele in Africans and Asians ma y contribute to an obesity and hypertension epidemic if Westernization of l ifestyles continues.