The INSIG1 rs2721/ rs9767875/ rs9719268 haplotype G-G-T and T-G-G were significantly associated with increased risk of obesity (OR = 1.984, 95% CI = 1.186-3.320, P = 0.008; OR = 1.512, 95% CI = 1.170–1.953, P = 0.001). This evidence concerns the gene INSIG1 and obesity due to melanocortin 4 receptor deficiency.