MGMT, a risk factor for both genetic and environmental forms of dementia.

MGMT, the gene coding for the DNA‐repair protein O6‐methylguanine methyltransferase, which has been recently shown to be a risk factor for inherited forms of Alzheimer's disease (AD), notably among women, might also be linked to Western Pacific amyotrophic lateral sclerosis and Parkinsonism‐dementia complex (ALS/PDC), one phenotype of which is an AD‐like dementia. Guam ALS/PDC is strongly considered to be an environmental disorder caused by oral exposure to natural toxins (i.e., genotoxic/epigenotoxic chemicals), notably methylazoxymethanol (MAM) that alkylates guanine to form O6‐methylguanine, found in the seed of cycad plants traditionally used for food. Thus, the DNA‐repair protein MGMT might participate in both AD and in the AD‐related disorder ALS/PDC. [ABSTRACT FROM AUTHOR]