A clinical, genetic, neuropathological study in a Japanese family with SCA 6 and a review of Japanese autopsy cases of autosomal dominant cortical cerebellar atrophy.

This report concerns a Japanese family with genetically confirmed SCA 6, including an autopsy case, and a review of Japanese autopsy cases of autosomal dominant cortical cerebellar atrophy (ADCCA). The proband (Case 1) was a Japanese woman. She developed gait disturbance at age 62. The father and younger sister (Case 2) had the same disorder. She died at age 67 due to subarachnoid hemorrhage. Neuropathological examination revealed severe loss of Purkinje cells in the cerebellum, prominently in the dorsal vermis, and absence of neuronal loss in the inferior olives. Molecular genetic study showed the CAG-repeat expansion of SCA 6 gene. The younger sister (Case 2) developed gait disturbance at age 62. Neurological examination at age 66 revealed cerebellar signs without sensory disturbance. Neuroimaging at this time showed cerebellar atrophy, prominently in the vermis. She died of multiple myeloma at age 66. A neuropathological review of Japanese autopsy cases of ADCCA showed that there are two patterns in the distribution of cerebellar cortical lesions of Japanese patients with ADCCA. The distribution of cerebellar cortical lesions in genetically confirmed Japanese patients with SCA 6 is more prominent in the vermis than in the hemisphere.