Background: In some populations, obesity and body weight related disorders show a correlation with polymorphisms in three subtypes of beta-adrenoceptor (β1, β2, and β3) [ADRB1, ADRB2 and ADRB3] genes. We scanned for the polymorphism of Arg389Gly (rs1801253) in ADRB1 and Trp64Arg (rs4994) in ADRB3 genes in Saudi population to determine association, if any, of these polymorphisms with obesity and related disorders.
Methods: We studied 329 non-related adults (33.1% men and 66.9% women), aged 18-36 years. Anthropometric measurements were recorded, and Body mass index (BMI) and waist/hip ratio were calculated; leptin, insulin, lipidogram, and glucose concentrations were determined. ADRB1 and ADRB3 polymorphisms (Arg389Gly and Trp64Arg, respectively) were screened by DNA sequencing. The subjects were divided into three groups according to BMI: normal weight (BMI < 25 kg/m2), overweight (BMI ≥25.1-29.9 kg/m2) subjects, and obese (≥30 kg/m2).
Results: In the age-matched groups of the normal weight, overweight and obese male and female subjects, all anthropometric parameters were found to be significantly higher, and in the obese group, all biochemical parameters were significantly elevated compared to the normal weight controls. The allelic frequency of Gly389 ADRB1 did not differ amongst the three groups, whereas the frequency of Arg64 of ADRB3 gene was significantly higher in the overweight and obese subjects, compared with the normal weight subjects. In addition, subjects carrying Arg64 allele regardless of their BMI had a greater waist and hip circumference, W/H ratio, plasma cholesterol, triglyceride, LDL, leptin, insulin, and glucose level compared to those with the wild-type Trp allele.
Conclusion: The results of this study have shown a significant association between the Trp64Arg polymorphism in ADRB3 gene and the development of overweight and obesity in Saudi populations. It also has an influence on the levels of lipid, insulin, leptin, and glucose, whereas, Arg389Gly polymorphism in ADRB1 is not associated with overweight, obesity or dyslipidaemias in Saudis.
Keywords: Dyslipidaemias; Obesity; Polymorphism; Saudi population; β1 adrenoceptor; β3 adrenoceptor; χ2 Chi square.