Ophthalmologic features of the common spinocerebellar ataxias

Purpose of review: The spinocerebellar ataxias (SCAs) are a phenotypically and genetically diverse group of autosomal dominant disorders that cause pathological degeneration in the cerebellum, brainstem, and retina, resulting in a wide variety of ophthalmologic signs and symptoms. Recent findings: The genetic discrimination of the SCAs has advanced dramatically over the past decade. The most common genetic (mutational) mechanism for the SCAs is an abnormal expansion to a stretch of glutamine amino acid residues (polyglutamine tract) encoded by any of several SCA-causing genes. Knowledge regarding the pathophysiology of polyglutamine-expansion-induced protein dysfunction is an area of intense investigation. Summary: The ophthalmologist may be the first to encounter a patient with SCA, and a review of the most common genetic subtypes of this disorder is helpful in diagnosis and management.