The encoded LRP5 protein, a member of the LDL receptor superfamily, acts as a coreceptor necessary for Wnt ligands to activate the pathway and regulates bone formation.11LRP5 was first identified in osteoporosis pseudoglioma syndrome (OPGG, MIM#259770), an exceptional recessive disease characterized by severe osteoporosis revealed in infancy and associated with a congenital blindness. This evidence concerns the gene LRP5 and osteoporosis.