Metatropic dwarfism, the Kniest syndrome and the pseudoachondroplastic dysplasias.

Metatropic dwarfism, the Kniest syndrome, and pseudoachondroplastic dysplasia are specific chondrodystrophic disorders that have in common dysplasia of the metaphyses, epiphyses, and vertebrae. Metatropic dwarfism and the Kniest syndrome have been confused with Morquio's disease and with each other in the past, but can be easily distinguished on the basis of radiographic features, clinical features, and cartilage pathology. The pseudoachondroplastic dysplasias are associated with short limbed dwarfism and have been confused with achondroplastic dwarfism, but can be readily distinguished on the basis of the normal head, delayed age of onset, the typical radiographic features and the cartilage pathology.