Hereditary multiple exostoses

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Hereditary multiple exostoses
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Synonyms	Diaphyseal aclasis, Multiple osteochondromas
Pronounce
Specialty	Orthopedics, Genetics
Symptoms	Multiple bony growths, limb deformities, restricted movement
Complications	Malignant transformation, nerve compression
Onset	Childhood
Duration	Lifelong
Types
Causes	Genetic mutation in EXT1, EXT2, or EXT3 genes
Risks	Family history
Diagnosis	Clinical examination, X-ray, Genetic testing
Differential diagnosis	Ollier disease, Metachondromatosis
Prevention	None
Treatment	Surgery for symptomatic lesions
Medication	Pain management
Prognosis	Generally good, but risk of complications
Frequency	1 in 50,000
Deaths	Rare

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Hereditary multiple exostoses

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Hereditary multiple exostoses

File:Multiple osteochondromas around the knee.jpg

Multiple osteochondromas around the knee

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Bone growth after hip replacement

Hereditary multiple exostoses (HME) is a medical condition characterized by the development of multiple benign (non-cancerous) bone tumors known as exostoses. This condition is inherited in an autosomal dominant manner, meaning that an affected person has a 50% chance of passing the disorder to each of their children.

Symptoms

The most common symptom of HME is the presence of multiple exostoses, which are often noticeable by early childhood. These exostoses can cause a variety of complications, including skeletal deformities, limited range of motion, and occasional pain. In rare cases, an exostosis may become malignant (cancerous).

Causes

HME is caused by mutations in one of two genes: EXT1 or EXT2. These genes are involved in the formation of heparan sulfate, a molecule that plays a critical role in the development and growth of bones.

Diagnosis

The diagnosis of HME is typically based on the presence of multiple exostoses. Genetic testing can confirm the diagnosis and identify the specific gene mutation causing the condition.

Treatment

There is currently no cure for HME. Treatment is focused on managing symptoms and may include surgery to remove exostoses that are causing complications.

Prognosis

The prognosis for individuals with HME varies. Most people with the condition have a normal lifespan, but complications such as malignant transformation of an exostosis can affect prognosis.

See also

• Bone tumor
• Genetic disorder
• Heparan sulfate