The skull in metaphyseal chondrodysplasia type Jansen.

For some reasons skull findings in Jansen's Metaphyseal Dysplasia have been largely neglected. A survey of the seven known cases (three of them being primarily observed and described by two of the authors) disclose important and constant alterations, namely pronounced basilar thickening and sclerosis, prominent supraorbital and zygomatic arches, underdevelopment of the paranasal sinuses with sclerosis of the adjacent bone, and hypoplasia of the mandible. These alterations give rise to distinct and fairly specific features. The relationship to other craniotubular disorders, such as craniodiaphyseal dysplasia, craniometaphyseal dysplasia, and frontometaphyseal dysplasia is discussed.