MC4R and obesity due to melanocortin 4 receptor deficiency: The initial GWAS demonstrated nominal association (p < 0.05) with variants in brain-derived neurotrophic factor (BDNF) and MC4R, but not in FTO. Variants in the genes KCNMA1 (potassium calcium-activated channel subfamily M alpha 1) and BDNF were reported to be associated with obesity at genome-wide significance.