Achondroplasia, hypochondroplasia and thanatophoric dysplasia: clinically related skeletal dysplasias that are also related at the molecular level.

This is the second of three articles on modern genetic concepts of a number of syndromes and disorders. Three short limb skeletal dysplasias with additional abnormalities of the skull are discussed. All are caused by mutations on fibroblast growth factor receptor 3 (FGFR3). A pathogenetic hypothesis is proposed to explain differences in the severity of short stature, midface deficiency, and craniosynostosis.