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We present genealogical and longitudinal clinical observations and autopsy findings of a previously reported kindred, Family C (German-American), with late-onset autosomal dominant parkinsonism with evidence for linkage on chromosome 2p13. The clinical phenotype includes the cardinal features of idiopathic Parkinson's disease. In addition, postural tremor and dementia are detected in some individuals. Two members of the kindred, one affected and one unaffected have recently come to autopsy. The unaffected family member was an 82-year-old woman whose brain showed only mild age-related pathology and no evidence of subclinical Lewy body disease. In contrast, the affected family member was an 83-year-old man whose brain had neuronal loss, gliosis and Lewy bodies in the substantia nigra and other monoaminergic brain stem nuclei, as well as the basal forebrain and amygdala. Lewy bodies and Lewy neurites had a distribution typical of cases of idiopathic Parkinson's disease. Thus, the clinical and pathological findings in this family with autosomal dominant parkinsonism are similar to those of sporadic Parkinson's disease.

In normal subjects, cerebral potentials were evoked by brief, passive extension of the wrist joint at various interstimulus intervals (ISIs). The resulting somatosensory evoked potentials (SEPs) were found to decrease during repetitive stimulation. The greatest decrement occurred between the first and second responses of each series. After cessation of stimuli, the SEP amplitude returned to control values over a prolonged, exponential time course. The authors postulate that the observed response decrement may be a form of habituation, which provides a model for studying the neuronal substrates of behavior.