A REVIEW ON ALZHEIMER'S DISEASE (A. D.)

Abstract

Major depression in late life and Alzheimer’s disease (AD) are disorders of enormous and increasing public health significance. In addition to early physical and intellectual challenges, individuals with Down syndrome are at a high risk for developing the symptoms characteristic of Alzheimer’s. People with Down syndrome develop the two hallmarks of Alzheimer’s disease amyloid plaques and tau tangles in their 30s and 40s. Due to improved clinical care, people with Down syndrome are now regularly living into their sixth decade of life, causing many to develop dementia due to Alzheimer’s. The high incidence of the symptoms characteristic of Alzheimer’s in people with Down syndrome is thought to be due to the extra copy of chromosome 21, which contains the gene that encodes the amyloid precursor protein (APP). APP is cleaved to form the amyloid-beta peptide; the primary component of plaques. It has been presumed that the extra copy of the gene produces an abnormally high amount of amyloid-beta. The cholinergic hypothesis was initially presented over 20 years ago and suggests that a dysfunction of acetylcholine containing neurons in the brain contributes substantially to the cognitive decline observed in those with advanced age and Alzheimer’s disease (AD).

KEY WORDS: Down syndrome, amyloid plaques and tau tangles, tretment.