[Effects of Trp64Arg mutation in the beta 3-adrenergic receptor gene on body fat, plasma glucose level, lipid profile, insulin secretion and action in Chinese].

OBJECTIVE

To ascertain the association of the Trp64Arg mutation in the beta 3-adrenergic receptor (ADRB3) gene with the total body fat and fat distribution, plasma glucose level, lipid profile, insulin secretion and action in Chinese.

METHODS

Genotyping of the Trp64Arg mutation in the ADRB3 gene as well as measurment of clinical variables body mass index(BMI), percent of desirable weight(PDW), area of regional adipose tissue depots, fasting lipid profile, and also, plasma glucose, insulin, C-peptide, free fatty acids levels before and after glucose challenge and blood pressure were performed in 308 Chinese, of whom, 161 were nondiabetics and 147, type 2 diabetic subjects.

RESULTS

(1) The frequency of Arg64 allele of ADRB3 gene in Chinese was similar to that in Japanese but slightly higher than that in Caucasians. (2) No association of any of the clinical varaibles with Trp64Arg mutation was observed in nondiabetics. (3) The Trp64Arg mutation in the ADRB3 gene was associated with BMI(P=0.019), PDW(P=0.001) and waist circumference (P=0.045) in type 2 diabetic subjects. In female diabetic subjects, more significant association with BMI(P=0.001), PDW(P=0.001), waist circumference(P=0.023), and also, association with abdominal and femoral subcutaneous fat area(P=0.032 and P=0.023) were observed. The frequencies of Arg64 allele were 21%, 14% and 4% in female diabetics with obesity, over-weight and normal-weight respectively (P=0.026). Logistic regression analysis showed that BMI was the only independent clinical variable related to the Trp64Arg mutation in the ADRB3 gene (P=0.0027).

CONCLUSION

The Trp64Arg mutation in ADRB3 gene contributes to the variation of total body fat in Chinese type 2 diabetic subjects.