LRP5 and osteoporosis-pseudoglioma syndrome: LRP5 is a well-known regulator of BMD and gain and loss of function mutations lead to high bone mass syndrome and osteoporosis pseudoglioma, respectively (Mizuguchi et al., 2004; Boyden et al., 2002; Marques-Pinheiro et al., 2010; Gong et al., 2001).