TaqIA polymorphism in dopamine D2 receptor gene complicates weight maintenance in younger obese patients

Abstract

Objective The A1 allele of the TaqIA polymorphism in the dopamine D2 receptor gene (rs1800497) has been associated with obesity. However, the effect of the polymorphism on the success in weight loss and/or weight maintenance during weight-loss programs has not been evaluated thus far. Methods The rs1800497 was genotyped in 202 (135 female, 67 male) severely obese individuals with an initial body mass index of 41.7 ± 0.5 kg/m2 who participated in a weight-loss program consisting of a weight-loss phase with a formula diet (12 wk) and a weight-maintenance phase (40 wk). Measurements were collected at baseline, after the weight-loss phase, and at the end of the weight-maintenance phase at 1 y. Results Genotyping revealed 4 A1A1, 67 A1A2, and 131 A2A2 genotype carriers. Of the 202 subjects in the program, 66.8% completed the program and 33.2% terminated prematurely. Neither the attrition rate (P = 0.44) nor the overall weight loss was influenced by the different genotypes (P = 0.96). However, younger A1+ participants (A1A1 and A1A2) had a higher body mass index at all time points (baseline, P = 0.04; after weight loss, P = 0.05; after weight maintenance, P = 0.02). They also showed less overall weight loss (P = 0.05), which derived mainly from a greater weight regain during the maintenance phase (P = 0.02). Conclusion In this program, younger A1+ participants exhibited problems in maintaining weight loss during a weight-loss program.