FTO and obesity due to melanocortin 4 receptor deficiency: However, we did not observe a clear association of this SNP with overweight-obesity, but only a trend with many exemptions, in agreement with other studies where some SNPs, previously reported to be involved in obesity, such as the rs17782313-MC4R and rs9939609-FTO, exerted weak effects and very scarce contribution to obesity in 773 pre-pubertal Portuguese children55.