SCA 6 with Writer's Cramp: The Phenotype Expanded.

Spinocerebellar ataxia type 6 (SCA6) presents typically with a pure cerebellar syndrome. Only 1 SCA 6 patient with writer's cramp has been reported on and a family history of ataxia and writer's cramp has never been reported on. Two other SCA6 patients with a shoulder girdle/hand dystonia and unspecified upper-limb dystonia with a family history of ataxia have been reported on. We report on the largest family with SCA6 and writer's cramp. The proband developed dysarthria, ataxia, and writer's cramp by age 37. His father presented with ataxia at 55, followed by writer's cramp and dysarthria. The proband's brother developed ataxia at 41, followed by dysarthria and writer's cramp. A paternal uncle (deceased; not examined) and 58-yr-old brother both developed pure ataxia (genetic testing is pending). This large family with complex movement disorder demonstrates that it is important to consider SCA6 in a patient presenting with an ataxia and writer's cramp and supports cerebellum involvement in dystonia.