[A case of 77-year-old male with spinocerebellar ataxia type 31 with left dominant dystonia].

We report on the case of a 77-year-old male with genetically proven spinocerebellar ataxia type 31 (SCA31) who had dystonia. He was referred to our hospital for evaluation following a 6-year history of slowly progressive unsteadiness of his left leg during walking and dysarthria at the age of 62 years old. On the basis of his symptoms, we diagnosed him as spinocerebellar degeneration (SCD), and prescribed taltirelin hydrate. However, his symptoms continued to worsen. He required a cane for walking at the age of 63 years, and a wheelchair at the age of 66 years. He was admitted to our hospital following acute cerebral infarction at the age of 77 years. On examination at admission, right hemiparesis and cerebellar ataxia were detected. And left hallux moved involuntarily toward the top surface of the foot at rest, that is dystonia. The dystonia was not associated with cerebral infarction, because it had been several years with dystonia that he got cerebral infarction. Genetic analysis revealed that this patient harbored a heterozygous SCA31 mutation. Previously there have been no reports of SCA31 associated with dystonia. Our case report support clinical heterogeneity of SCA31, and highlight the importance of considering this type in patients with dystonia and ataxia. Patients with the combination of dystonia and ataxia and a family history of a neurodegenerative disorder should be tested for SCA31.