Apoliproprotein E polymorphism is a major susceptibility factor for late onset AD, and is located on chromosome 19. The process of AD begins with degeneration of hippocampal neurons, causing short-term memory to falter. This may be mistaken for Amnesia . As AD spreads through the cerebral cortex it begins to take away language. As the disease progresses, disturbing behaviours e.g. wandering and agitation occur.
AD wipes out the ability to recognise even close family members or to communicate in any way.
The average length of time between diagnosis of AD and death is 4-8 years, but it can be 20 years or more.