The contribution of mitochondrial dysfunction to a gene–environment model of Guamanian ALS and PD

Scientific investigations of amyotrophic lateral sclerosis (ALS) and parkinsonism–dementia (PD) of Guam have implicated genetic and environmental risk factors in their etiology. Using brain tissue, we investigated mitochondrial dysfunction and report a higher frequency of somatic mutations in the light strand promoter (LSP) of the mitochondrial control region in Guam ALS and PD patients than in Guam controls, along with the presence of inherited mutations that may contribute to a novel gene–environment interaction risk model. Along with other risk factors, they demonstrate both the importance and significance of genetic and environmental contributions to Guam ALS and PD etiology.