Dystonia

Causes of Dystonia

In primary or idiopathic dystonia, dystonia occurs as a solitary symptom and is not associated with an underlying disorder. Many cases are believed to be hereditary and occur as the result of a faulty gene(s). For example, most cases of early-onset primary dystonia are due to a mutation in the DYT-1 gene. Early-onset dystonia that occurs as a result of this disease gene is the most common and severe type of hereditary dystonia. Other, rarer, genetic causes of primary dystonia are also known.

In secondary or symptomatic dystonia, dystonia occurs because of another underlying disease process. The list of possible causes is long, and includes:

• Wilson disease
• multiple sclerosis
• stroke
• brain trauma
• medications

In adults, the most common type of secondary dystonia is tardive dystonia, due to dopamine-blocking drugs. In most patients, symptoms occur some time after ongoing exposure to the drug. Other movement disorders may also be caused by neuroleptics, the most common of these being dyskinesia.