K. ABE, MD, T. KAMEYA, MD, M. TOBITA, MD, H. KONNO, MD, and Y. ITOYAMA, MD spinocerebellar ataxia type 1 (SCA1) is an autosoma1 dominant neurodegenerative disorder usually characterized by cerebellar ataxia, ophthalmoparesis, and pyramidal However, the patients sometimes develop muscle wasting. Neuropathological findings define SCAl as an atrophy of the brain stem and cerebellum with loss of neurons in the inferior olivae, pontine nuclei, Purkinje's cells, and dentate nuclei, as well as degeneration of the spinocerebellar tracts and motor neurons of the spinal cord. g Although a possible relationship between muscle wasting and loss of motor neurons has been pointed out in patients with SCAl, few works have been reported on the mechanism of the muscle wasting and motor neuronal death in relation to the number of the trinucleotide CAG repeat and course of the disease. Twenty patients with SCAl (14 males and 6 females) were clinically and genetically examined according to previous reports. 2.6 DNA from blood lymphocytes was amplified by polymerase chain reaction (PCR), and accurate repeat numbers were estimated with a fluorescein isothiocyanate-labeled primer by an automated DNA~ equencer.~ Three of the 20 patients showed marked muscle wasting, and therefore,