The A19G polymorphism in the 5 ' untranslated region of the human obese gene does not affect leptin levels in severely obese patients

Recently, the presence of different polymorphisms in the regulatory region of the ob gene has been associated with variations in leptin levels. Howeve r, the results of these studies are still contradictory. The aim of the pre sent investigation was to evaluate the presence of the A19G polymorphism in an Italian population of obese patients and to verify its association with leptin levels and anthropometric, metabolic, and clinical parameters. Two hundred five obese patients [body mass index (BMI) > 36 kg/m(2); 135 women and 70 men; mean age, 46.9 +/- 14.23 yr] were screened for presence of the polymorphism; 61 normal-weight controls (mean BMI, 21.05 kg/m(2); 53 women, 8 men) were also screened to compare polymorphism frequency. For obese pat ients, BMI, waist-to-hip ratio, resting energy expenditure, body compositio n, fasting leptin, total cholesterol, high-density lipoproteins, triglyceri des, and caloric intake were determined. Genotype frequencies in obese and control subjects were compared using the contingency table chi-square test; in obese subjects an ANOVA was performed to evaluate association between t he polymorphism and several clinical parameters. No significant differences in genotype distribution between control and obese subjects were found. No significant correlations were found between this polymorphism and serum le ptin levels and the other parameters considered. These findings confirm the results obtained in both a Finnish and a French population; taken together , these observations might rule out a significant role for the A19->G polym orphism in the regulation of leptin levels and other clinical, anthropometr ic, and metabolic parameters.