Progressive supranuclear palsy-like syndrome in two siblings of a consanguineous marriage.

Two siblings of a consanguineous marriage showed identical clinical features consisting of supranuclear vertical ophthalmoplegia, bradykinesia, rigidity, stooped posture, pseudobulbar palsy, and dementia, all beginning in the sixth decade. There was no history of encephalitis or of exposure to known chemicals. L-Dopa therapy was only partially and temporarily effective. Autopsy of one patient revealed extensive neurofibrillary degeneration with prominent involvement of the limbic system. There were no senile plaques or Lewy bodies. Under electron microscopy, there were paired helical filaments as well as 15-nm-wide straight tubules. The diffuse appearance of neurofibrillary tangles, predominant in the limbic system, and familial occurrence are unusual in progressive supranuclear palsy; these cases may, therefore, constitute a different, distinctive clinicopathologic disease.