Association of G-2548A LEP polymorphism with plasma leptin levels in Tunisian obese patients

Objectives: The aim of this study was to examine the association of the G-2548A polymorphism of the human leptin gene (LEP) with body mass index (BMI), plasma leptin, insulin, and lipid parameters in a sample of Tunisian population. Design and methods: Two hundred and twenty nine obese patients (BMI ≥ 30 kg/m2) were screened and compared to 251 normal weight subjects (BMI < 25 kg/m2). The human leptin gene promoter G-2548A genotype was determined by polymerase chain reaction followed by a digestion with the restriction of endonuclease CfoI. Results: In the entire study sample, carriers of -2548A allele had significantly lower leptin levels than homozygous for -2548G allele (14.28 ± 9.10 ng/mL vs. 18.27 ± 12 ng/mL, p < 0.001 respectively) adjusted for BMI and gender. In obese patients but not control, subjects carrying the -2548A allele exhibited lower leptin levels than those with GG genotype (16.96 ± 8.27 ng/mL vs. 21.37 ± 11.72 ng/mL, p = 0.001 respectively) adjusted for BMI and gender. In this group, carriership of the -2548A allele was identified, by multiple linear regression models, as significant independent predictor for leptin levels variability. Separate analyses by gender revealed that only in obese women, the -2548A allele was found to be associated with lower leptin levels independently of BMI (p = 0.004). Conclusions: The present study showed that G-2548A LEP polymorphism is associated with lower leptin levels in Tunisian obese women. © 2008 The Canadian Society of Clinical Chemist.