X-linked olivopontocerebellar atrophy.

We present a kindred with a relatively pure cerebellar degeneration that demonstrates X-linked recessive inheritance. The unique clinical picture of affected patients in our kindred is characterized by an infantile onset of ataxia; very slow rate of progression; normal strength, reflexes, and sensation; and cerebellar degeneration with involvement of the olive and pons demonstrated by neuroimaging techniques. The distinction between this and other reported olivopontocerebellar degenerations is made on the basis of the clinical features and mode of inheritance. It is not clear if the distinct clinical pattern in this kindred represents variable expression of a previously reported condition, allelic variance of previously reported kindreds, or a separate clinical entity. Molecular analysis, currently underway, may help settle the issue.