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>or=30 kg/m(2)) were screened and compared to 251 normal weight subjects (BMI<25 kg/m(2)). 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.