It is a very rare inherited disorder characterized by short stature with abnormally short arms and legs (short-limbed dwarfism). Other physical characteristics may include outward “flaring” of the lower rib cage, genu varum, pain in the legs, and/or hip deformities (coxa vara). Such abnormalities of the legs and hips typically result in an unusual “waddling” gait.
Metaphyseal Dysplasia, Schmid Type; Schmid Metaphyseal Dysplasia; Japanese Type Metaphyseal Dysplasia; Metaphyseal Dysplasia Japanese Type.
It was first described in 1949 by F. Schmid, a German researcher.
Congenital anomaly of collagen located in the metaphyses.
The exact incidence remains unknown. It affects males and females in equal numbers.
Autosomal dominant with variable expression; de novo mutations not rare.
Mutation in COL10A1 gene for collagen type X, alpha 1, the expression of which is restricted to the hypertrophic zone of the growth plate. This explains the metaphyseal location of the disease and the mechanical weakness of the growth plates in these patients.
Clinical picture, but rickets and causes of hypophosphatasemia should be excluded.
Moderate short stature, bowed legs, coxa vara, waddling gait are associated with this disorder. Irregular metaphyses, but the radiological picture can temporarily disappear after prolonged bed rest. Enlarged femoral capital epiphyses. No vertebral anomalies. Adult height: approximately 130 to 160 cm (51.2-63 inches).
Because of the numerous skeletal anomalies, positioning of the patient must require special attention.
J: Metaphyseal chondrodysplasia, Schmid type. Clinical and radiographic delineation with a review of the literature. Pediatr Radiol
WG: Early-onset metaphyseal chondrodysplasia type Schmid associated with a COL10A1 frame-shift mutation and impaired trimerization of wild-type α1(X) protein chains. J Orthop Res
DL: Schmid type metaphyseal chondrodysplasia: A spondylometaphyseal dysplasia identical to the “Japanese” type. Pediatr Radiol