There are a large number of well recognised syndromes comprising cerebellar ataxia in association with other neurological features. We report three family members who presented with a relapsing, early onset cerebellar ataxia, associated with progressive optic atrophy and sensorineural deafness. All three patients have areflexia (in the absence of a peripheral neuropathy), a pes cavus deformity, and show varying degrees of severity. Extensive neurological investigations have been normal, and the aetiology and pathophysiology of this disorder remain unclear. This may represent a separate syndrome of early onset cerebellar ataxia with associated features ("cerebellar ataxia plus"), which is likely to either have an autosomal dominant or maternal mitochondrial pattern of inheritance. The recognition of this association under the acronym of CAPOS (cerebellar ataxia, areflexia, pes cavus, optic atrophy, and sensorineural deafness) may help in the delineation of a new syndrome.