Clinical neurogenetics: dystonia from phenotype to genotype.

Dystonia can arise from genetic syndromes or can be secondary to nongenetic injuries; both causes can produce pure dystonia, dystonia plus other movement disorders, or paroxysmal mixed movement disorders. Genetic causes of dystonia are inherited through dominant, recessive, X-linked, and mitochondrial mechanisms, may show anticipation, are variably penetrant, and may be limited to small ethnic populations or single families. In this article, the genetic causes of dystonia, an algorithm for their diagnosis and management, information on common medications and surgical treatments, and resources for affected families and those interested in advancing research are presented.