MC4R and obesity due to melanocortin 4 receptor deficiency: Third, the effect of MC4R polymorphism on obesity related traits (e.g. BMI, waist circumference, fat mass percentage) were not assessed in the meta-analysis since the data provided by the original publications were not uniform, i.e., several studies provided mean and standard deviation (or 95%CI) across each genotype, while other studies provided beta and 95% CI, which impeded the further data analysis.