Huntington's Disease Assistance Foundation

What is HD?

Huntington’s disease, chorea, or disorder (HD), is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and dementia. It typically becomes noticeable in middle age. HD is the most common genetic cause of abnormal involuntary writhing movements called chorea. It is much more common in people of Western European descent than in those of Asian or African ancestry. The disease is caused by an autosomal dominant mutation on either of an individual’s two copies of a gene called Huntingtin, which means any child of an affected parent has a 50% risk of inheriting the disease.

For more scientific details visit the HD page on Wikipedia