New form of familial Parkinson-dementia syndrome: clinical and pathologic findings.

We studied a family in which three siblings had a syndrome characterized by parkinsonism features, mental deterioration, pyramidal signs, and abnormal eye movements beginning in the third decade. The pathology resembled that of progressive supranuclear palsy or the Parkinson-dementia complex of Guam, but these were excluded by the clinical presentation. This syndrome appears to be a new entity.