Hereditary ataxia in a large Danish pedigree.

A Danish pedigree with olivo-ponto-cerebellar ataxia, transmitted as an autosomal dominant trait through six generations, has been studied. Forty-nine individuals were affected, and the main signs were staggering, ataxic gait, dysmetria and dysarthria. Early symptoms were always imbalance and clumsiness. Clinical features varied greatly, and many types of heredo-familial ataxia had previously been assigned to the family members. Ten had been diagnosed as having multiple sclerosis (MS), although symptoms typical of MS, such as paresthesias, mental disturbances and optic atrophy were extremely uncommon. The variations in the clinical picture show that the manifestations of a single dominant gene may appear to mimic different clinical entities unless the genetic evidence is taken into account.