Walsh & Hoyt: Congenital Cerebellar Ataxias

Congenital ataxia may be related to dysgenesis or agenesis of the vermis, cerebellar hemispheres, or brainstem, as occurs in such conditions as the Dandy-Walker syndrome and Chiari malformations. Dysgenesis of the cerebellum is often associated with rather nonspecific clinical signs. These include abnormal motor development and hypotonia at an early stage. With time, nystagmus, impaired coordination on reaching for an object, and truncal ataxia develop. The frequent association with mental retardation and spasticity often leads to a diagnosis of ataxic cerebral palsy, especially if there is no family history. It is estimated that about 50% of these cases are of autosomal-recessive inheritance.