Abstract
Background and Objectives: In this study, we aimed to investigate the link between common -2548G>A (rs7799039) promoter variant of the human leptin gene (LEP) with leptin and serum glucose leptin levels in obese Saudi patients. Materials and Methods: A total of 206 Saudi adults (80 obese normotensive nondiabetics, 76 obese hypertensive with Type 2 Diabetes and 50 normotensive nondiabetic controls) were genotyped for -2548G>A LEP polymorphism using the polymerase chain reaction-restriction fragment-length polymorphism technique. Results: Participants with minor AA genotype had significantly higher blood glucose levels (6.8 +/- 0.55 mmol/L vs. 5.8 +/- 0.30 mmol/L; p < 0.04) and HOMA-IR (4.1 +/- 0.84 vs. 2.6 +/- 0.67; p = 0.03) against those carrying major GG genotype. Participants with heterozygous GA genotype had significantly higher serum leptin levels against those carrying major GG genotype (40.0 +/- 2.6 ng/mL vs. 29.6 +/- 2.6 ng/mL; p = 0.04). Further investigation showed that individuals with AA, GA, GA + AA genotypes are at greater risk of developing hyperglycemia compared to those with GG genotype [OR 3.7(1.6-8.4), p = 0.001; 3.2 (1.2-8.6), p = 0.03; 3.5 (1.6-7.7), p = 0.001, respectively]. Additionally, the -2548AA allele was shown to be a risk factor for hyperglycemia [OR 1.9 (1.2-3.0), p = 0.006]. Our data revealed no relationship between this variant of the LEP gene with systolic and diastolic BP, signifying that this genetic variant is not a significant marker of obesity and hypertension in the Saudi population. Conclusions: AA and GA genotypes and LEP gene -2548AA alleles may signify potent risk factors predisposing healthy individuals to develop T2DM regardless of blood-pressure profile.