However, the above-mentioned findings could also be due to—at least in some patients—variants in the melanocortin receptor 2 (MC2R) gene, which might increase responsiveness to ACTH; in fact, we reported MC2R linkage and association to/with T2D; one variant was the opposite allele of the variant causing glucocorticoid deficiency syndrome [60]. Here, MC2R is linked to type 2 diabetes mellitus.