Association Between a Polymorphism in the β3-adrenergic ReceptorGene and Childhood Obesity

Genetic factors of obesity that have recently been revealed include the β3-adrenergic receptor (β3AR) gene. The aim of this study is to examine the possible role in childhood obesity of a mutation in the β3AR gene. This study examined 72,139,and 48 Japanese obese children at 7,10,and 13 years of age, respectively. Polymorphism in the β3AR gene was analyzed using a polymerase chain reaction and the restriction enzyme of BstNI as well as serum levels of lipids and insulin in fasting blood samples. Analyses revealed seven Arg64 homozygotes, 101 Trp64/Arg64 heterozygotes, and 151 Trp64 homozygotes. Seven-year-old subjects with the mutation (n=27) had a larger relative weight (154.8±10.6%), higher ponderal index (kg/m^3) (19.0±1.3), and higher levels of triglyceride (95.6±46.0 mg/dl) and insulin (9.3±3.0μ U/ml) than those without the mutation (n=45) (149.3±8.9%, 18.3±1.1,74.8±31.4mg/dl, and 7.6±2.5μU/ml, respectively, p<0.05). In either 10 or 13-year-old, no significant differences were observed in the above mentioned parameters between subjects with or without the mutation. These results suggest that a polymorphism in the β3AR gene contributes to obesity and is associated with hyperinsulinemia and hypertriglyceridemia in younger obese children.