Hereditary spinocerebellar ataxias: number, prevalence, and treatment prospects.

The autosomal dominant spinocerebellar ataxias (ADSCA) are a group of late-onset neurodegenerative disorders. Since the elucidation of the genetic basis of these disorders, the clinical term ADSCA has been replaced by that of spinocerebellar ataxias (SCAs). In most families with SCA, progressive ataxia is not an isolated symptom but occurs in combination with a variety of other neurological features— a finding that suggests extra-cerebellar involvement. In pathological terms, SCAs are characterised by the degeneration of the cerebellum, brainstem, and their efferent or afferent nerve fibres.