We report 14 patients with a slowly progressive syndrome featuring ataxia, choreoathetosis, and ocular motor apraxia in both the horizontal and vertical planes. Although the neurological signs were indistinguishable from those of ataxia-telangiectasia, the onset tended to be later and none of the patients had evidence of multisystemic involvement. Specifically, there was no tendency to frequent infections, and immunoglobulins, alpha-fetoprotein, T- and B-lymphocyte markers, and chromosomes 7 and 14 were normal in all tested patients. The simultaneous absence of telangiectasias and of other nonneurological manifestations made ataxia-telangiectasia an unlikely diagnosis. We suggest that these patients suffer from an unusual type of spinocerebellar degeneration. This syndrome has been observed in different populations from three continents, with a genetic pattern suggesting recessive autosomal inheritance.