amyotrophic lateral sclerosis-parkinsonism-dementia complex

Lytico-bodig disease

Lytico-Bodig (also Lytigo-bodig) disease, Guam disease, amyotrophic lateral sclerosis-parkinsonism-dementia complex (ALS-PDC), and Western Pacific amyotrophic lateral sclerosis-parkinsonism-dementia complex is a rare, terminal neurodegenerative disease of uncertain etiology endemic to the Chamorro people of the island of Guam in Micronesia. Lytigo and bodig are Chamorro language words for two different manifestations of the same condition. ALS-PDC, a term coined by Asao Hirano and colleagues in 1961, reflects its resemblance to amyotrophic lateral sclerosis (ALS), Parkinson's disease, and Alzheimer's disease. First reports of the disease surfaced in three death certificates on Guam in 1904 which made some mention of paralysis. The frequency of cases grew amongst the Chamorro until it was the leading cause of adult death between 1945 and 1956. The incidence rate was 200 per 100,000 per year and it was 100 times more prevalent than in the rest of the world. Neurologist Oliver Sacks detailed this disease in his book The Island of the Colorblind. Sacks and Paul Alan Cox subsequently wrote that bats had been feeding on Federico nuts (Cycas micronesica) and concentrating β-methylamino-L-alanine (BMAA), a known neurotoxin, in their body fat. The hypothesis suggests that consumption of the bats by the Chamorro exposed them to BMAA, contributing to or causing their condition. Decline in consumption of the bats has been linked to a decline in the incidence of the disease.