Spondylometaphyseal dysplasias

**Definition:** Spondylometaphyseal dysplasias are a heterogeneous group of disorders associated with walking and growth disturbances that become evident during the second year of life. The disorders are characterised by platyspondyly (flattened vertebrae) and marked hip and knee metaphyseal lesions. The different forms of spondylometaphyseal dysplasia are distinguished by the localization and severity of involvement of the affected metaphyses.