The different effects of a Gln27Glu β2-adrenoceptor gene polymorphism on obesity in males and in females

Abstract

Objectives. To investigate the role of a polymorphism in codon 27 (Gln27Glu) of the β2-adrenoceptor gene for obesity in males compared to previously investigated females with an association of this polymorphism to obesity. Design. Population-based study. Setting. Medical department at a University Hospital. Subjects. A total of 138 non-related Swedish males with body mass indexes (BMI) in the range 19.4-53.4 kg m-2 were recruited as: healthy volunteers, healthy obese subjects and subjects undergoing surgery for uncomplicated gallstone or abdominal hernia. In order to investigate the impact of gender, the results were compared with a subset of an earlier investigated female population of 109 Swedish females. Obesity was defined as a BMI > 27 kg m-2. Main outcome measures. Genotype examination of β2- adrenoceptor polymorphism in codon 27 with polymerase chain reaction and restriction fragment length polymorphism. Results. The allele frequency of Gln27 and Glu27 did not differ between males and females when obese and non- obese subjects were investigated together. However, in obese males, the frequency of the Glu27 allele was significantly decreased (P = 0.034), whereas the frequency of this allele was increased in obese females (P = 0.013). No impact of the female androgen status on the distribution of the Gln27Glu polymorphism could be demonstrated in the obese females. Conclusion. A positive association between obesity and the Glu27 genetic variant in the β2-adrenoceptor exists in females, whereas in males there is a negative correlation between Glu27 and obesity. The findings suggest that different genetic factors contribute to obesity in males and females.