Metaphyseal anadysplasia

Metaphyseal anadysplasia (also known as metaphyseal anadysplasia type 1 or type 2) is a rare skeletal disorder characterized by metaphyseal abnormalities of the long bones that tend to spontaneously improve or resolve with age. The condition primarily affects the skeletal system, particularly the metaphyses (the growing ends) of long bones such as the femora and tibiae. It typically presents in infancy or early childhood with short-limbed short stature, bowing of the legs, and a waddling gait. Radiographic findings include irregular, widened metaphyses with radiolucent areas resembling rickets, but biochemical markers of calcium and phosphorus metabolism are normal, distinguishing it from true rickets. There are two recognized forms: type 1 (OMIM 602111), which is inherited in an autosomal dominant pattern and is associated with mutations in the MMP13 gene, and type 2 (OMIM 613073), which is inherited in an autosomal recessive pattern and is associated with mutations in the MMP9 gene. Both MMP13 and MMP9 encode matrix metalloproteinases involved in bone remodeling and extracellular matrix degradation, which are critical for normal skeletal development. A hallmark feature of metaphyseal anadysplasia is its self-correcting nature. The metaphyseal irregularities and short stature tend to improve significantly during childhood, and many affected individuals achieve near-normal or normal adult height. Because of this benign natural history, treatment is generally conservative and supportive. No specific medical or surgical intervention is typically required, though orthopedic monitoring during childhood is recommended to track skeletal development and ensure appropriate resolution of bony abnormalities. Genetic counseling is advised for affected families.

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