Sclerostin defects are responsible for the metabolic bone disorders known as SOST-related sclerosing bone dysplasia, which include three different entities: Sclerosteosis (MIM 269500), Van Buchem Disease (VBD; MIM 239100), and the SOST-related craniodiaphyseal dysplasia (CDD; MIM 122860) [4]. The gene discussed is SOST; the disease is sclerosteosis.