Association between MC4R rs17782313 genotype and obesity: A meta-analysis

Background: Obesity is a huge burden of the world. It is commonly recognized that dietary structure and physical inactivity is essential in the progress of obesity. However, some individuals still face the trouble of obese even though they live a healthy life. Except for the combination of diseases, the operation of both lifestyle and genetic features contributes to obesity. Melanocortin-4-receptor (MC4R) gene is one of the known hereditary factors of obesity. rs17782313, a single nucleotide variant in MC4R gene, has been reported unclear results in whether it plays a role in obesity. This meta-analysis is to estimate the association between MC4R rs17782313 genotype and obesity.

Method: A systematic literature retrieval was conducted in four databases: PubMed, Embase, Web of Science and Cochrane Library with specific search strategy. Select qualified studies to identify relevant studies. Odds ratios (ORs) with 95% confidence intervals (CI), P value and I² value were used to assess the strength of the association in meta-analysis and adjusted with ethnicity, quality and single nucleotide polymorphism (SNP) testing method.

Result: 6 eligible studies involving 3133 obese cases and 3123 normal-weight participants were selected from 378 articles. Allele B of MC4R rs17782313 present a statistically significant association with obesity under allele contrast model (OR = 1.325, 95%CI: 1.219-1.439), dominant model (OR = 1.320, 95%CI: 1.184-1.472), recessive model (OR = 1.690, 95%CI: 1.420-2.011) and homozygous type of co-dominant model (OR = 1.925, 95%CI: 1.590-2.330), respectively, and P < 0.05.

Conclusion: Mutated MC4R rs17782313 is associated with higher risk of obesity. People with homozygous mutant genotype of MC4R rs17782313 would be more likely to suffer from obesity, while heterozygous mutant genotype needs further studies to clarify.