What Is Early-Onset Alzheimer’s Disease?
Hereditary Disease Strikes Young
Early-onset Alzheimer’s is when Alzheimer’s disease affects people before they reach 65. It is also called younger-onset Alzheimer’s. More than five million people in the U.S. live with this brain disease that robs people of their ability to think and remember. Four percent of these five million have early-onset Alzheimer’s. Read on to learn about who is affected and when to be concerned.
Rare and Devastating
Early-onset Alzheimer’s can strike people in their 30s or 40s, but this is rare. A person who develops Alzheimer’s in their 50s is considered to have the early-onset form of the disease. Because early-onset Alzheimer’s runs in families, people affected at a younger age may already be providing care for an older relative with the disease.
An Unwelcome Family Trait
The cause of early-onset Alzheimer’s is genetic. One of the genetic causes is “deterministic genes.” Researchers have identified deterministic genes in a few hundred families worldwide. These genes provide the unfortunate guarantee that developing Alzheimer’s is inevitable. Multiple members of different generations develop what is known as “familial Alzheimer’s disease.”
Three Rare Genes
All our genetic information—everything from hair and eye color to risk of certain diseases—is encoded in the 23 pairs of chromosomes each of us has. There are three rare deterministic genes that have been found to cause early-onset Alzheimer’s disease:
- Amyloid precursor protein (APP): This protein was discovered in 1987 and is found on the 21st pair of chromosomes. It provides instructions for making a protein found in the brain, spinal cord, and other tissues.
- Presenilin-1 (PS-1): Scientists identified this gene in 1992. It is found on the 14th chromosome pair. Variations of PS-1 are the most common cause of inherited Alzheimer’s.
- Presenilin-2 (PS-2): This is the third gene mutation found to cause inherited Alzheimer’s. It is located on the first chromosome pair and was identified in 1993.
Risk vs. Fate
It’s important to understand that the three aforementioned genes that cause early-onset Alzheimer’s disease differ from APOE, the gene that raises your risk of Alzheimer’s. The presence of this gene indicates higher risk of Alzheimer’s but does not guarantee that someone will develop it. People who have the APOE gene have an elevated risk of the disease. Alzheimer’s will affect not everyone who has this gene.
Early-Onset Does Not Progress Faster
People with early-onset Alzheimer’s do not progress more quickly through the mild, moderate, and severe phases of the disease. The disease progresses over the course of several years in younger people. It also does so in adults older than 65. When younger people reach a stage that requires additional care, this may create the impression that the disease has moved more quickly.
When to Worry
Most of us experience momentary memory lapses. Misplacing keys, blanking on someone’s name, or forgetting a reason for wandering into a room are a few examples. These do not signal the serious cognitive changes associated with early-onset Alzheimer’s. The symptoms of early-onset Alzheimer’s are the same as the common form of the disease. Worrisome signs include:
- difficulty following a recipe
- inability to balance a checking account (beyond the occasional math error)
- getting lost en route to a familiar place
If you are younger than 65 and experience these kinds of changes, talk with your doctor.
Testing and Diagnosis
Diagnosing early-onset Alzheimer’s disease is not simple. No single test can confirm the disease. In younger people, symptoms may be mistakenly attributed to anxiety, depression, alcohol use, or medication side effects. Consult an experienced physician if you have a family history of early-onset Alzheimer’s. He or she will take a complete medical history and conduct a detailed medical and neurological exam. The diagnostic process may also include magnetic resonance imaging (MRI) or computed tomography (CT) scans of the brain. There may also be blood tests in order to rule out other disorders.
Genetic Testing for Early-Onset Alzheimer’s Disease
You may have a sibling, parent, or grandparent who developed Alzheimer’s before age 65. If so, you may want to consult a genetic counselor in addition to seeing your physician. Genetic testing can determine if you carry one of the three deterministic genes that cause early-onset Alzheimer’s.
The decision to have this test is a personal one. Some people choose to learn whether they have the gene in order to prepare as much as possible with financial planning, consulting with their employer, and completing an advance directive.
Get Help Early
If you are concerned that you may have early-onset Alzheimer’s, don’t delay talking with your doctor. While there is no cure for the disease, certain medications such as donepezil (Aricept), rivastigmine (Exelon), galantamine (Razadyne), and memantine (Namenda) may help in managing symptoms. Staying physically active and keeping connected with friends and family for support are also important in maintaining quality of life with Alzheimer’s at any age.
- Alzheimer’s disease: How the disease progresses. (2013, January 4). Mayo Clinic. Retrieved November 21, 2013, from http://www.mayoclinic.com/health/alzheimers-stages/AZ00041
- APP. (2012, May). Genetics Home Reference. Retrieved November 21, 2013, from http://ghr.nlm.nih.gov/gene/APP
- Early-Onset Alzheimer’s Disease. (n.d.). Johns Hopkins Medicine. Retrieved November 21, 2013, from http://www.hopkinsmedicine.org/healthlibrary/conditions/nervous_system_disorders/early-onset_alzheimers_disease_134,63/
- Early-onset Alzheimer’s: When symptoms begin before age 65. (2011, March 31). Mayo Clinic. Retrieved November 21, 2013, from http://www.mayoclinic.com/health/alzheimers/AZ00009
- What We Know Today About Alzheimer’s Disease. (2013). Alzheimer’s Association. Retrieved November 21, 2013, from http://www.alz.org/research/science/alzheimers_disease_causes.asp#genetics
- Younger/Early Onset Alzheimer’s & Dementia. (2013). Alzheimer’s Association. Retrieved November 21, 2013, from http://www.alz.org/alzheimers_disease_early_onset.asp