Spectrum of Schwartz-Jampel syndrome includes micromelic chondrodysplasia, kyphomelic dysplasia, and Burton disease

Follow-up and re-evaluation of four patients originally described as examples of severe infantile "micromelic chondrodysplasia" resembling Kniest disease, "kyphomelic dysplasia," and "Burton skeletal dysplasia" revealed the diagnosis of Schwartz-Jampel syndrome (SJS, myotonic chondrodysplasia) in all of them. SJS may be suspected in neonates with Kniest-like chondrodysplasia, congenital bowing of shortened femora and tibiae, and facial manifestations consisting of a small mouth, micrognathia, and possibly pursed lips. The disorder must be differentiated from the Stüve-Wiedemann syndrome, a genetically distinct myotonic chondrodysplasia with similar clinical but different skeletal changes and an unfavorable early prognosis. The demise of "kyphomelic dysplasia" as a nosological entity reemphasizes the symptomatic nature of congenital bowing of the long bones.