Effect of Trp64Arg mutation of the β3-adrenergic receptor gene and C161T substitution of the peroxisome proliferator activated receptor γ gene on obesity in Japanese children

Objective: Obesity is a multifactorial syndrome influenced by both genetic and behavioral factors. Trp64Arg mutation of the beta3-adrenergic receptor (AR) gene and C161T substitution of the peroxisome proliferator-activated receptor (PPAR) gamma gene have been reported to be associated with obesity or lipid metabolism in adults. However, the effects of these mutations on children have not yet been clarified. For this reason, we studied the effects of Trp64Arg mutation of the beta3-AR gene and C161T substitution of the PPARgamma gene on obesity in Japanese children. Subjects and Methods: In order to determine the effects of Trp64Arg mutation of the beta3-AR gene and C161T substitution of the PPARgamma gene on obesity in children, 105 obese Japanese children were screened by the polymerase chain reaction and restriction fragment-length polymorphism analysis. Plasma lipid, apolipo-protein (apo), glucose, insulin and leptin levels were also determined. Results: Obese boys with Trp64Arg showed a higher obesity index and lower plasma levels of high-density lipoprotein cholesterol (HDL-C), apoA-I and apoA-II than those of them without the mutation. Obese boys with both mutations showed a higher plasma leptin level than those with only the beta3- AR gene mutation or PPARgamma gene mutation. No significant effect of these mutations was found in obese girls. Conclusion: All of these data suggest that Trp64Arg mutation of the beta3-AR gene might affect obesity and HDL metabolism in obese boys. In contrast, C161T mutation of the PPARgamma gene, by itself, is unlikely to influence obesity, lipid metabolism or plasma leptin levels.