LRP6 and osteoporosis: Romosozumab, a monoclonal antibody against sclerostin, represents a new class of anti‐osteoporosis drug, recently approved by the FDA.3, 4 Sclerostin, a key inhibitor of bone formation, was discovered through study of two rare syndromes of extreme high bone mass (HBM) due to mutations in SOST. 5, 6SOST encodes Sclerostin, which binds to low‐density lipoprotein receptor‐related proteins 5 and 6 (LRP5 and LRP6) to prevent activation of canonical WNT signaling in bone, resulting in decreased bone formation.