Alzheimer∆s patients typically live from five to 10 years after diagnosis, though with recent improvements in health care, they can live for 15 years or more. The disease is particularly stressful on those who have to care for these patients, particularly as the disease progresses. Risk factors for Alzheimer∆s include head trauma, age, Down∆s syndrome, and a genetic mutation.
Familial Alzheimer∆s disease accounts for approximately 10 percent of cases, and some of these patients develop symptoms before age 40 (Gale, 2001). The early onset genes are found on chromosomes 1, 14, and 21, and are termed presenilins. The gene on chromosome 14 appears to be primarily responsible for early onset Alzheimer∆s disease, which has a more rapid course. The presenilin on chromosome 1 seems to be responsible for Alzheimer∆s of later onset, with a more protracted course. Recently, genetic studies have shown that the gene for apolipoprotein E (ApoE), a protein which moves cholesterol in the bloodstream and can bind to amyloid beta-protein, can affect the chances of getting Alzheimer∆s disease. There are three forms of ApoE - ApoE2, ApoE3, and ApoE4. They are normally occurring variants, and it has been found that the inheritance of ApoE4 increases the risk and lowers the age of onset of the disease, and inheritance of ApoE2 decreases the risk and raises the age of onset. The gene is