[A sporadic case of dentatorubral-pallidoluysian atrophy (DRPLA) having an elderly age of onset].

We reported a sporadic case of DRPLA that had an elderly age of onset. The patient was a 71-year-old woman. Her parents, sisters and a brother didn't have neurologic diseases. She had been well until the age of 68 years, when she noticed her unstable gait. On neurologic examination cerebellar ataxia and a tremor at the neck were noticed, but we were unable to differentiate her disease from the other types of spinocerebellar degeneration. An MRI of the cranium showed atrophy of the cerebellum, pons, brain stem and cerebrum, and a diffuse lesion of the cerebral white matter. These findings made us suspect her disease of DRPLA. When we analyzed the CAG repeat in the DRPLA gene, we found it expanded to 57. We thought that the elderly onset related to a relatively mild expansion.