Metaphyseal chondrodysplasia, Schmid type

Metaphyseal chondrodysplasia, Schmid type (MCDS), also known as Schmid-type metaphyseal chondrodysplasia, is a relatively common form of metaphyseal chondrodysplasia — a group of skeletal disorders affecting the growing ends (metaphyses) of long bones. It is caused by mutations in the COL10A1 gene, which encodes type X collagen, a protein essential for normal bone development at the growth plate. The condition primarily affects the skeletal system, leading to short stature that typically becomes apparent in early childhood when the child begins to walk. Key clinical features include short-limbed short stature (particularly affecting the legs), bowing of the legs (genu varum), a waddling gait, coxa vara (abnormal angle of the hip joint), and flaring of the lower rib cage. Radiographic findings characteristically show metaphyseal irregularities, widening, and cupping, most prominently at the knees, hips, and wrists. The skull and spine are generally unaffected, which helps distinguish MCDS from other skeletal dysplasias. Intelligence is normal, and there are no significant extraskeletal manifestations. There is currently no specific cure or disease-modifying therapy for Schmid-type metaphyseal chondrodysplasia. Management is primarily supportive and symptomatic. Orthopedic interventions, including corrective osteotomies, may be considered for significant leg bowing that causes functional impairment or pain. Growth hormone therapy is generally not effective. The prognosis is favorable, as affected individuals typically achieve a final adult height in the low-normal to mildly short range, and the skeletal abnormalities tend to improve somewhat after the growth plates close. Regular orthopedic and clinical monitoring during childhood is recommended.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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