A recessively inherited ataxia with episodes of dystonia

A family with recessively inherited ataxia and dystonic episodes that responded to antiepileptic medication is described. The onset was in the first decade. Clinically the patients have gait and limb ataxia, nystagmus and brisk reflexes, with abnormal visual, auditory and somatosensory evoked responses, but normal nerve conduction velocities and electromyography. Their intelligence is borderline. CT and MRI scans show severe atrophy in the vermis and basis pontis.