Pilot study examining the frequency of several gene polymorphisms in a morbidly obese population.

Background: Obesity is a growing problem and is associated with numerous medical conditions. Several polymorphisms have been associated with lipid metabolism and obesity: PPAR-gamma2-Pro115Gln, PPARgamma2-Pro12Ala, beta3AR-Trp64Arg and SR-BI IVS5 C > T. We examined the frequency of these polymorphisms in patients with a BMI > 40 and compared them to individuals with a BMI < 30. Our hypothesis was that these polymorphisms would occur more frequently in the obese population.

Methods: This case-control study examined 126 individuals with a BMI > 40 in the McGill University Health Centre Bariatric Surgery Program and 102 individuals (controls) with a BMI < 30 attending a Lipid Clinic. DNA was extracted from whole blood by standard techniques. The polymorphisms were determined by polymerase chain reaction (PCR) and restriction genotyping.

Results: A significant difference between controls and the morbidly obese group was observed for 2 of 4 polymorphisms. The carrier frequency for PPARgamma2-Pro12Ala was 24.8% in the obese group and 12.9% in controls (odds ratio = 2.2; 95% CI = 1.1-4.4; P = 0.02). The carrier frequency for SR-BI IVS5 C > T was 22.8% in obese individuals versus 8.1% in controls (odds ratio = 3.5; 95% CI = 1.6-7.7; P = 0.002). There were no differences in frequency of diabetes in both obese (13/104) and control (9/126) groups (odds ratio = 1.86, 95% CI = 0.76 < O.R. < 4.54, P = 0.184).

Conclusions: These results underscore the relationship between gene polymorphisms and obesity. Obese individuals may differ from non-obese individuals in the gene polymorphisms associated with metabolic control.