GTR Home > Conditions/Phenotypes > Multiple congenital exostosis

Disease characteristics

Excerpted from the GeneReview: Hereditary Multiple Osteochondromas
The disorder hereditary multiple osteochondromas (HMO), previously called hereditary multiple exostoses (HME), is characterized by growths of multiple osteochondromas (benign cartilage-capped bone tumors that grow outward from the metaphyses of long bones). Osteochondromas can be associated with a reduction in skeletal growth, bony deformity, restricted joint motion, shortened stature, premature osteoarthrosis, and compression of peripheral nerves. The median age of diagnosis is three years; nearly all affected individuals are diagnosed by age 12 years. The risk for malignant degeneration to osteochondrosarcoma increases with age, although the lifetime risk of malignant degeneration is low (~1%).

Associated genes

Clinical features

  • Coxa vara
  • Short stature
  • Rib exostoses
  • Pelvic exostoses
  • Peripheral nerve compression
  • Scapular exostoses
  • Protuberances at ends of long bones
  • Madelung-like forearm deformities
  • Abnormality of the foot
  • Cervical myelopathy
  • Genu valgum
  • Chondrosarcoma
  • Short metacarpal
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