Degeneration of the substantia nigra in familial amyotrophic lateral sclerosis.

We have studied a large family with familial amyotrophic lateral sclerosis (FALS) and examined the brain and spinal cord of a 40-year-old male family member at autopsy three years after clinical onset of the disease. The most unusual finding was a severe degree of neuronal loss of the substantia nigra accompanied by gliosis and numerous pigment-laden macrophages. There was marked degeneration of the upper and lower motor neurons and the corticospinal tracts. In addition, there was an unusually severe degree of diffuse degeneration throughout the anterolateral columns of the spinal cord. The posterior columns and Clarke's nucleus were not involved. Nigral degeneration has rarely been reported in FALS. The findings in this case emphasize the great variability of morphologic changes encountered in FALS and raise the question of a relationship between FALS and extrapyramidal disorders such as Parkinson's disease. We conclude that careful postmortem examinations of further cases of FALS are needed to fully define the extent of degenerative changes in this disease.