Hereditary multiple osteochondromas

Description

Hereditary multiple osteochondromas is a condition in which people develop multiple benign (noncancerous) bone tumours called osteochondromas. The number of osteochondromas and the bones on which they are located vary greatly among affected individuals. The osteochondromas are not present at birth, but approximately 96 percent of affected people develop multiple osteochondromas by the time they are 12 years old. Osteochondromas typically form at the end of long bones and on flat bones such as the hip and shoulder blade.

Multiple osteochondromas can disrupt bone growth and can cause growth disturbances of the arms, hands, and legs, leading to short stature. Often these problems with bone growth do not affect the right and left limb equally, resulting in uneven limb lengths (limb length discrepancy). Bowing of the forearm or ankle and abnormal development of the hip joints (hip dysplasia) caused by osteochondromas can lead to difficulty walking and general discomfort. Multiple osteochondromas may also result in pain, limited range of joint movement, and pressure on nerves, blood vessels, the spinal cord, and tissues surrounding the osteochondromas.

Osteochondromas are typically benign; however, in some instances these tumours become malignant (cancerous). Researchers estimate that people with hereditary multiple osteochondromas have a 1 in 20 to 1 in 200 lifetime risk of developing cancerous osteochondromas (called sarcomas).

Inheritance patterns

The source lists the following possible inheritance patterns: Autosomal dominant. More than one pattern can apply in different cases.

Related genes

• EXT1

• EXT2

Other names

Bessel-Hagen disease

Acclasie diaphysaire

Exostoses, multiple hereditary

Familial exostoses

Hereditary multiple exostoses

Multiple cartilaginous exostoses

Multiple congenital exostosis

Multiple hereditary exostoses

Multiple osteochondromas

Multiple osteochondromatosis