Adult GM1 gangliosidosis: immunohistochemical and ultrastructural findings in an autopsy case.

We report neuropathologic findings for a 66-year-old Japanese man with adult/chronic GM1 gangliosidosis whose main clinical symptoms were speech and gait disturbance attributable to dystonia with rigidity. He was a homozygote for the 51isoleucine (ATC)-->threonine (ACC) mutation in the beta-galactosidase gene. Neuronal loss and intracytoplasmic storage were most prominent in the caudate nucleus and putamen and, to a lesser degree, in the amygdala, globus pallidus, and Purkinje cells in the cerebellum. Other areas of the CNS were relatively spared. We believe that this selective neuronal involvement in the CNS is characteristic of adult/chronic GM1 gangliosidosis and that it reflects a more active turnover of GM1 ganglioside in the affected areas than elsewhere in the CNS.