Background: Leptin, an adipocyte-derived hormone, has a pivotal role in the regulation of body weight through acting on its specific leptin receptor (LEPR). The 223A/G polymorphism of the LEPR gene is one of the most common polymorphism in all populations. In this study, we aimed to investigate the impact of the 223A/G polymorphism of the LEPR gene on serum levels of leptin in type 2 diabetes mellitus (T2DM) in a sample of Iranian population.
Materials and methods: One hundred and forty-four T2DM patients were screened and compared to 147 healthy controls. The 223A/G LEPR polymorphism was genotyped using polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP). The serum levels of leptin were measured.
Results: The mean serum levels of leptin in T2DM patients were significantly higher than that of healthy control subjects; 22.90 ng/ml (95 % confidence interval [CI] = 20.79 - 25.23) vs. 8.70 ng/ml (95 % CI = 7.87 - 9.63). The genotypes (AA, AG, and GG) distributions of the 223A/G polymorphism were 55.5 %, 41 %, and 3.5 % in T2DM and 54.4 %, 42.2 %, and 3.4 % in healthy controls. The results showed no significant differences in the 223A/G LEPR genotype and allele frequencies between T2DM and control subjects (χ2 = 0.043, P = 0.979 and χ2 = 0.003, P = 0.957), respectively. In addition, the serum leptin levels were markedly higher in subjects with GG genotype than those with AG or GG genotype only in T2DM CONCLUSION: The 223A/G LEPR gene polymorphism is associated with markedly increased serum leptin levels in T2DM. However, no differences were determined in genotype and allele frequencies between T2DM patients and control subjects.