Association of leptin–melanocortin gene polymorphisms with the risk of obesity in northwest Indian population

Obesity, a multifaceted endocrine issue, is adversely affecting all age groups and is posing a significant public health challenge. The genetic polymorphisms of the melanocortin 4 receptor (MC4R) and leptin (LEP) genes likely contribute to the development of obesity. The present study aimed to explore the effects of MC4R and LEP gene polymorphisms on obesity among the northwest Indian population. The present study was conducted among 333 obese cases and 338 non-obese controls (aged 18–50 years). All subjects underwent measurements for anthropometric, physiometric, as well as biochemical parameters. Genotyping for MC4R and LEP gene variants was performed using the polymerase chain reaction (PCR)-based restriction fragment length polymorphism (RFLP) method. However, 10% of the samples for each variant were confirmed using the Sanger sequencing method. The polymorphisms of leptin–melanocortin pathway genes (MC4R-LEP) were found to be significantly associated with various obesity-related parameters like waist circumference: p = 0.017, waist-to-height ratio: p = 0.009, total cholesterol: p = 0.0001 and triglycerides: p = 0.0001. Both the LEP gene variants rs2167270 and rs7799039 conferred 2.4- and 2.2-fold risk toward obesity under the recessive genetic model [OR (95% CI) 2.42 (1.44–4.07), p = 0.001; OR (95% CI) 2.26 (1.41–3.60), p = 0.0001, respectively]. All four polymorphisms of the MC4R and LEP genes demonstrated a strong interaction of 82.1% with the lifestyle factor (p = 0.001). The haplotype combinations A–A for rs571312 and rs12970134 conferred twofold risk [OR (95% CI) 2.61 (1.10–6.20), p = 0.028]. However, the combination A–G for rs2167270 and rs7799039 predicted sixfold risk [OR (95% CI) 6.02 (3.39–10.68), p = 0.0001] toward the obesity development in this population. Our study revealed a connection between MC4R (rs571312, rs12970134) and LEP (rs2167270, rs7799039) gene variants with obesity, highlighting their prominent role in assessing the risk of obesity among the northwest Indian population.