Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing repetitive movements and/or abnormal postures. Dystonic movements are typically patterned and twisting, affecting the neck, torso, limbs, eyes, face, vocal chords, and/or a combination of these muscle groups. The movements may be associated with tremor.
There are a number of different forms of dystonia, and many diseases are associated with the condition. Dystonia can be classified clinically and/or etiologically by anatomic changes (nervous system pathology) and causation (inherited, acquired, or idiopathic). Classifying dystonia by clinical features includes age of onset, body distribution, temporal pattern, and associated features.
Hereditary dystonias are usually inherited in an autosomal dominant manner and less commonly in an autosomal recessive or X-linked manner.
Indications for genetic testing:
1. Confirmation of clinical diagnosis
2. Carrier testing for at-risk relatives
3. Prenatal diagnosis for known familial mutation
4. Genetic counseling
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