LRP5 and osteosclerosis: The complex Wnt pathway is believed to be important for osteogenic differentiation, as loss-of-function mutations in low-density lipoprotein receptor-related protein 5 (LRP5—a co-receptor of WNT) were found to cause osteoporosis-pseudoglioma syndrome, while gain-of-function mutations in LRP5 caused osteosclerosis [146,149].