Two cases of spinocerebellar ataxia accompanied by involvement of the skeletal motor neuron system and bulbar palsy.

We report two patients with spinocerebellar ataxia (SCA) with cranial and spinal motor neuron involvement. They initially presented with cerebellar ataxia, followed by bulbar palsy and limb motor neuron sign. One of the patients had a brother with allied disorder. SCA type 1 (SCA1), SCA3 and SCA6 have been reported to involve the motor neuron system, but they were excluded by DNA analyses in the present two patients. These two patients may form a distinct disease entity among SCAs.