Can overmethylation cause dementia?

No: Dementia is usually differentiated into two types: vascular type, and non-vascular type. Vascular dementia is due to disruption in the vascular supply causing degeneration of neurons. Non-vascular dementia, such as Alzheimer's dementia, Lewy body dementia are cause by mechanisms involve amyloid plaque depositions and neurofibrillary tangles, and accumulation of Lewy body in the neuron.