Nigral degeneration in neuroacanthocytosis.

We counted nerve cells in different subregions of the substantia nigra in three patients with neuroacanthocytosis and compared the results with those of age-matched Parkinson's disease and control patients. Two patients with neuroacanthocytosis and clinical parkinsonism in life had a reduced neuronal density in the substantia nigra, while in a third patient without parkinsonism, this number was at the lower limit of the control range. In neuroacanthocytosis with parkinsonism and in Parkinson's disease, the ventrolateral region of the substantia nigra was most severely affected, although in neuroacanthocytosis cases, nigral neuronal loss was more widespread.