We report three patients with severe pontocerebellar atrophy (PCA) associated with a variable degree of cerebral atrophy. The clinical features consisted of progressive microcephaly, central hypotonia, visual impairment, abnormal eye movements and delayed psychomotor development. These are similar but not identical to the features of pontocerebellar hypoplasia type 2 described by Barth. The picture also differs from the classical form of autosomal dominant olivopontocerebellar atrophy. While in two patients the disease seemed to be genetic with highly suspicious autosomal recessive inheritance, the etiology in the third patient was probably nongenetic. We suggest that PCA is a morphologic entity with distinct radiologic features but variable clinical, pathophysiologic and etiologic backgrounds.