The following case reports describe a new condition of cerebellar ataxia, anterior horn cell disease, dystonia, and learning difficulties. Four cases are described. The condition appears to be of autosomal recessive inheritance as the group is made up of two pairs of sisters. All cases were evident by 3 years of age. Anterior horn cell disease was of a type not previously described at this age in association with cerebellar ataxia. Further genetic studies suggest the condition is not allelic with spinal muscular atrophy having no evidence of deletion of the survival motor neurone gene.