BGLAP and obesity due to melanocortin 4 receptor deficiency: Several studies have suggested roles for osteocalcin in regulating metabolism, behavior and cognition based on a mouse model lacking osteocalcin (Lee et al., 2007; Oury et al., 2013), and further studies found that daily injections of exogenous osteocalcin decreased the severity of diet-induced obesity and glycemic control in a mouse model of T2DM (Ferron et al., 2008, 2012).