Genetic Advances in Alzheimer Disease

The terms senility, dementia, forgetfulness are used interchangeably to describe the confusion and memory loss that often results from the normal aging process. The terms can be confusing and difficult to distinguish. Many diseases that begin in adulthood and are associated with aging have both environmental and genetic components. Alzheimer disease (AD) is the most common cause of dementia in both early and late onset dementia.

The first case of AD was described in 1906 by Alois Alzheimer. It is a non-discriminatory disease affecting males and females, all ethnic groups, and all income levels in society. With the recent death of a former governor of South Carolina and with the increasing numbers of families with affected family members, public attention and scientific research are expanding.

What do we know about this disease? It is the most common cause of dementia and an estimated 100 billion dollars per year is spent caring for the 4 million AD patients. AD is a major public health problem in the elderly population.

There are specific clinical signs that characterize this disease. Patients are generally unable to learn and process new information. Patients experience short term memory loss, are subject to hallucinations, and may experience difficulty in expressive language. Aggression, depression, sleep disturbances, and the tendency to wander are common characteristics of the AD patient. These symptoms can progress until the patient is bedridden and incapable of self-care. The duration of AD is approximately seven to ten years. Specific changes in the brain are noted in this condition including the formation of plaques of certain chemicals and other changes that can be seen under the microscope.

The genetic understanding of AD is continuing to evolve but there is much yet to learn. Early onset of the disease is defined as younger than age 60. Early-onset families transmit AD in a dominant manner. Gene mutations or changes known to be involved in early-onset disease are noted in genes on chromosomes 1, 14, and 21. For late-onset families (older than 60), there is no clear genetic cause but suspected genes include a version of the ApoE gene (a cholesterol related gene) on chromosome 19.

Other possible risk factors for AD are the presence of free radicals which are formed through the normal aging process, low levels of vitamins C and E, low estrogen levels in women, and head injury which may cause inflammation.

Treatment for AD is still a work-in-progress. Various treatments are continuing to evolve but some of the more common medications used include Aricept, Exelon, and Reminyl, all with variable results. Estrogen and NSAIDS or anti-inflammatory agents are also being investigated as potential treatments. For more information on Alzheimer Disease, you may visit the Alzheimer’s Association at http://www.alz.org

Special thanks to Dr. Robert Saul