MC4R and obesity due to melanocortin 4 receptor deficiency: However one recent well-powered study by Elks et al. found a modest association between an obesity risk score comprising alleles from FTO, MC4R, TMEM18, GNPDA2, KCTD15, NEGR1, BDNF and ETV5 (SFRS10) loci and BMI at birth in 7,146 individuals.