OBJECTIVETo investigate the G-protein beta 3 subunit (GNB3) gene 825C/T polymorphism and its relationship to obesity in Chinese population.

METHODSThree hundred and ninety nine subjects (270 non-obese and 129 obese individuals) from a population of Chinese Han nationality in Chengdu area were studied using PCR-restriction fragment length polymorphisms (PCR-RFLPs). Serum lipids were measured by enzymatic kits and apolipoproteins A I, A II, B100, C II, C III and E were measured by RID kits.

RESULTSThe frequencies of C and T alleles at the 825C/T site in obese and non-obese groups were 0.531 and 0.469, and 0.528 and 0.472, respectively. It showed no significant difference in both genotypes and allele frequencies between the non-obese and obese groups (P> 0.05). The frequency of T allele at 825C/T site in GNB3 gene in the population (0.471) was significantly higher than that of German white (0.319), lower than that of African black (0.788), and similar to that of Japanese (0.487). In the non-obese group, subjects with genotype TT had higher serum triglyceride(TG) concentrations than those with genotype CT (P< 0.05). In the obese group, subjects with genotype CC had lower serum high-density lipoprotein cholesterol(HDL-C) levels than those with CT genotype (P< 0.05). Similar results were only observed in non-obese male and obese female subgroups, respectively, when male and female subgroups were further separated in the two groups. In addition, non-obese males with genotype TT and obese females with genotype CC had lower HDL-C and higher apoA I levels than those with genotype CT, respectively. Obese males with genotype TT had higher apoA I levels than those with genotype CC.

CONCLUSIONThe 825C/T polymorphism in the GNB3 gene was not associated with obesity in Chinese Han population of Chengdu area. However, it may be associated with serum triglyceride, HDL-C and apoAI levels, with some gender-specific effect, in this population.