Autosomal dominant spinocerebellar atrophy with retinal degeneration.

The autosomal dominant cerebellar ataxias are a clinically and genetically heterogeneous group of disorders. In one unique form, early loss of color discrimination with macular degeneration is followed by gradual progression of cerebellar dysfunction and development of pyramidal signs. Pathology shows degeneration of cerebellum, basis pontis, inferior olive, and retinal ganglion cells. This disorder is genetically distinct from the other autosomal dominant cerebellar ataxias, consistent with the unique clinicopathologic features of this form of ADCA. Profound anticipation is noted in families with this phenotype and suggests that a trinucleotide repeat expansion may be the cause of this disease. Genetic characterization of this unique disorder may allow better understanding of the pathophysiology seen in these patients and provide insight into the nature of this and other neurodegenerative disorders.