The discovery of the importance of the Wnt-signaling pathway in bone metabolism [reviewed in 3] and studies of patients with rare skeletal disorders characterized by high bone mass identified sclerostin—a natural inhibitor of the Wnt pathway that reduces bone formation—as a target for the development of new therapeutics that may fulfill the requirements for improved treatment for osteoporosis [4–6]. Here, SOST is linked to osteoporosis.