A neurodegenerative disease, also known as Lytico-Bodig, that affects about one percent of native residents of Guam (the indigenous Chamorro population), typically manifested in late midlife. In Guam ALS-PDC the person has parkinsonism, Alzheimer’s dementia, and amyotrophic lateral sclerosis (Lou Gehrig’s disease) concurrently and typically eventually shows symptoms of all three, although one or two may be more prominent at onset or throughout the course of the disease. Scientists do not know why this complex of disease occurs in this particular population but believe that because it seems to occur only in this population there are strong genetic (hereditary) factors, though there have been strong arguments that an environmental agent may be the culprit.
In its early stages Guam ALS-PDC is sometimes misdiagnosed as one of its component diseases, although the true nature of the condition becomes obvious within a few years as the degeneration progresses rapidly. Damage to the brain often also includes the tangles and plaques of Alzheimer’s disease, giving rise to the belief that this disease involves extensive and complex deterioration affecting nearly all of the brain. Treatment attempts to manage the symptoms but is not very effective. Plaques, tangles, and protein deposits characteristic of Parkinson’s, Alzheimer’s, and ALS are widespread throughout the brain at autopsy.