CALCR and obesity due to melanocortin 4 receptor deficiency: AmyR consist of a calcitonin receptor (CTR) associated with a receptor activity-modifying protein (Hay et al., 2015), and some ligands activate both AmyR and CTR, which has generated interest in dual amylin/calcitonin receptor agonists (DACRAs) for obesity treatment (Sonne et al., 2021).