Other causes of ataxia in patients with SCA mutations.

Autosomal dominant spinocerebellar ataxias (SCAs) are slowly progressive and have a variable clinical presentation. Overlapping clinical features among the SCAs make the clinical diagnosis of these ataxias difficult. Even when genetic testing identifies an SCA mutation, clinicians should be vigilant for other causes of neurological dysfunction in these patients. We report two patients who developed other causes of ataxia in the setting of SCA-3 and SCA-8 mutations, respectively.