Hereditary juvenile parkinsonism with pyramidal signs and mental retardation.

We describe two patients who developed, in the first and second decades of life, mental retardation, some limitation of up gaze, poorly levodopa-responsive parkinsonism and pyramidal signs. Recessive inheritance is suggested by the fact that they were subsequently found to be first cousins from consanguineous unions. A number of different possible diagnoses were considered, but despite extensive investigation these patients, who are both still living, thus far appear to be unique. In particular, unlike most cases of alleged "pallido-pyramidal disease" in the literature, we do not feel it justifiable to use this denomination in the absence of either pathological or in vivo imaging evidence of pallidal involvement.