Search for a red cell enzyme or serum protein marker in amyotrophic lateral sclerosis and parkinsonism-dementia of Guam.

Frequency distributions were determined for 24 red cell enzyme and four serum protein systems, in an attempt to identify a genetic marker associated with either amyotrophic lateral sclerosis (ALS) or parkinsonism-dementia (PD), two progressive and fatal neurological disorders of unknown cause found with unusually high incidence among the Chamorros of Guam and the Northern Mariana Islands. No striking associations were identified between either disorder and any of the gene markers tested. Thus, no genetic cause is known for either disease; local environmental factors are most likely involved in pathogenesis.