DNA & Alzheimer's Disease

The National Institute on Aging states that researchers still do not know the causes of Alzheimer's Disease (AD), the most common form of dementia in the elderly. However, scientists identify the likely culprits---heredity, environment and lifestyle---as contributors to this mental deterioration. The latter two conditions vary by circumstance. And although genetics plays a large role in increasing a person's risk factors, most answers do not reside definitively in the chromosomes.

Types

• Both early-onset and late-onset Alzheimer's Disease tends to run in families. Patients may exhibit symptoms of early-onset AD between the ages of 30 and 50; while people over 60 may show signs of the late-onset disease. In either case, AD begins years before the first symptoms appear. Both begin with a buildup of amyloidal (protein) plaques and tangles in the brain. And both have genetic markers that indicate increased susceptibility.

Identification

• Currently, seven genes help researchers identify potential for AD. Dr. Marcelle Morrison-Bogorad, director of the division of neuroscience at the National Institute on Aging, says the risk for getting Alzheimer's later in life increases, dependent on the number of copies of the ApoE-4 gene. Morrison-Bogorad links three others to early-onset illness: the APP, PS1 and PS2 genes. Additionally, recent European projects from the University of Lille and Cardiff University claim CLU, CR1 and PICALM relate to late-onset Alzheimer's. Ask your physician to explain these to you.

Effects

• The Lille study suggests risk increases by 20 percent to 25 percent for people who carry the CLU or the CR1 genes. Morrison-Bogorad cites a 50 percent likelihood of inherited Alzheimer's exists for about 10 percent of early-onset patients. However, most of these indicators merely reflect the potential for late-onset AD. Those with family histories for early-onset Alzheimer's will benefit more from genetic testing.

Features

• Memory problems (relative to age group) remain the foremost factor in identifying AD. Recent studies suggest deteriorating motor and thinking skills may also provide warnings, along with problems with the sense of smell. Unfortunately constancy among these signs varies from day-to-day with Alzheimer's patients. Emotional problems such as anger, anxiety or depression also provide indicators.

Prevention/Solution

• No cure for Alzheimer's Disease currently exists, but researchers are testing various pharmaceutical options. Research goals include stopping plaque from forming or spreading, developing a vaccine, and preventing gene mutation. Scientists are also investigating physical and mental exercises that will slow or prevent the disease. Early diagnosis buys time, and some drugs will slow the progression of AD for months or years, though an ultimate cure remains elusive.