Association of Trp64Arg mutation of the β_3-adrenergic receptor gene with obesity in school-age Japanese children

The β_3-adrenergic system plays an important role in regulating the energy balance through thermogenesis and lipolysis in white and brown adipose tissues. Recently, a possible pathogenic mutation in human β_3-AR genes (codon64 TGGTrp→CGGArg; Trp64Arg) has been reported to be associated with obesity and insulin resistance among several population. We investigated the Trp64Arg mutation of the β_3-AR gene in 450 school-age Japanese children. One group of 225 children (121 boys and 104 girls) with a mean age of 11.7 and an obesity index greater more than twenty percent constituted the obese group. Two hundred and twenty-five non-obese children were matched to each obese subject for gender and for age to the control group. The allele frequency of this mutation in the obese group was significantly higher than that in the control group (0.24 versus 0.12, p<0.01). The prevalence of this mutation was also significantly more increased in the obese group than in the control group (44.0% versus 24.0%, x^2=11.3, p<0.001). Significantly higher blood pressure was observed in obese subjects with this mutation than in obese subjects without mutation after correction for gender, age, and body weight (systolic; 112.3±11.7mmHg versus 108.2±11.8mmHg, p<0.01 and diastolic; 63.2±8.4mmHg versus 60.2±8.3mmHg, p