Association of leptin receptor gene Q223R polymorphism on lipid profiles in comparison study between obese and non-obese subjects.

OBJECTIVES: Leptin is a hormone secreted from adipocytes. It regulates metabolism and energy homeostasis through the leptin receptor (LEPR) which is localized centrally in hypothalamus as well as in peripheral tissues. The aim of this study was to investigate the association of leptin receptor gene Q223R polymorphism on obesity in association with body mass index (BMI), lipid parameters, plasma leptin levels and homeostasis model assessment of insulin resistance (HOMA-IR).

DESIGN AND METHODS: The study included 110 obese and 90 non-obese subjects. The LEPR Q223R polymorphism was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Plasma leptin levels, serum lipid and antropometric parameters were measured.

RESULTS: No association was found between LEPR gene Q223R polymorphism and BMI in both study and control groups. Strikingly study group with non-obese subjects and with the RR genotype (homozygous mutant) had significantly higher serum total cholesterol (p<0.001) and low density lipoprotein cholesterol (LDL-cholesterol) levels (p<0.05) than QR (heterozygous) and QQ (wild type) genotypes. In obese group, subjects with the RR genotypes had significantly higher triglycerides (p<0.05) levels, waist (p<0.05) and hip circumferences (p<0.001) than the QQ and QR genotypes.

CONCLUSIONS: Our results suggest that the LEPR gene Q223R polymorphism has an association with waist and hip circumferences in obese group but no direct association with obesity although there is a significant influence on lipid profile both in obese and non-obese subjects.