Early Onset Alzheimer's Disease: Facts and Information

Young-onset (also called early-onset) Alzheimer's is a unique form of dementia affecting people younger than 65. About 5% to 6% of people with Alzheimer's develop symptoms before age 65. Most people with young-onset Alzheimer's develop symptoms of the disease when they are between 30 and 60 years old. What are the risks for early-onset Alzheimer's disease? Family history of the disease is the only known risk factor.

The U.S. Social Security Administration (SSA) has included Early Onset Alzheimer's Disease as a Compassionate Allowance to expedite a disability claim.

Main Content

Symptoms of Early Onset Alzheimer's Disease (EOAD)

Alzheimer's disease usually starts with subtle symptoms and, therefore, poorly recognized, such as memory failure. Over the years, the person's memory loss slowly becomes increasingly severe, eventually incapacitating. Other symptoms that are common to Alzheimer's disease include:

• Mutism
• Agitation
• Myclonus
• Confusion
• Withdrawal
• Incontinence
• Hallucinations
• Seizure Activity
• Poor Judgment
• Language Disturbance
• Parkinsonian Features
• Increased Muscle Tone

People affected by Alzheimer's disease who die commonly perish as a result of malnutrition, general inanition, and pneumonia.

Causes of EOAD

Medical science has identified three genes associated with early-onset familial Alzheimer's disease. These genes include:

• PSEN1: This gene mutation is associated with Alzheimer's disease type 3, which accounts for thirty to seventy percent of early-onset familial Alzheimer's disease.
• PSEN2: This gene's mutation is associated with Alzheimer's disease type 4. PSEN2 has been identified by the medical community in a few families living in the United States, in three Italian kindreds, two Italian kindreds, and two Spanish families. Mutations in PSEN2 account for less than five percent of all early-onset familial Alzheimer's disease.
• APP: Mutations in this gene are associated with Alzheimer's disease type 1, which accounts for approximately ten to fifteen percent of early-onset familial Alzheimer's disease.

Kindreds with autosomal dominant early-onset familial Alzheimer's disease who do not have identifiable mutations in PSEN1, PSEN2, or APP genes have also been described. Mutations in other genes are likely a cause of EOAD.

Diagnosing EOAD

A diagnosis of early-onset Alzheimer's disease can be obtained in families that have multiple members who are affected by the disease with a mean age onset of before age sixty-five who have a documented, disease-causing mutation in one of the genes that are known to be associated with the disease. There are three clinically indistinguishable subtypes of early-onset Alzheimer's disease based on the underlying mechanism. These subtypes include:

• Alzheimer disease type 1 (AD1), caused by mutations in APP
• Alzheimer disease type 3 (AD3), caused by mutations in PSEN1
• Alzheimer disease type 4 (AD4), caused by mutations in PSEN2

There are molecular genetic tests for PSEN1, PSEN2, and APP available for families through clinical laboratories.

Alzheimer's disease can be diagnosed in people who present with slowly progressing dementia without other causes of dementia and cerebral cortical atrophy through neuroimaging studies. A post-mortem diagnosis can be achieved by examining intraneuronal neurofibrillary tangles and beta-amyloid neuritic plaques.

Treatment of EOAD

Treatment of Alzheimer's disease is largely supportive. Treatment for aggression, depression, seizure activity, sleep disturbances, and any hallucinations the person may experience are all managed individually.

People who are affected by Alzheimer's disease eventually require the services of either assisted living, a nursing home, or other forms of long-term care services.

They require agents that increase cholinergic activity, such as donepezil, galantamine, or rivastigmine, that tend to provide some yet variable benefit. There is a medication called 'memantine,' that is an NMDA receptor antagonist, approved for use with Alzheimer's disease as well.

People affected by Alzheimer's disease may benefit from occupational and physical therapies to assist with managing activities of daily living. They should avoid over-sedation and sudden changes to their environment.

Early-onset Alzheimer's disease is inherited in an autosomal dominant manner, meaning that most people with EOAD have a parent affected by the disease. Occasionally, neither person's parents have been identified as having the disease. However, a second-degree relative, such as an uncle, an aunt, or perhaps a grandparent, has or experienced early-onset Alzheimer's disease.

Children of people with EOAD have a fifty-percent chance of inheriting the gene mutation for the disease and developing EOAD. Prenatal testing for mothers at increased risk of having a child with EOAD with a PSEN1 mutation is available. Prenatal testing for mothers at increased risk of having a child with a PSEN2 or APP mutation might be available through laboratories that offer custom prenatal testing. Prenatal testing for adult-onset disorders, however, is unusual.

Author Credentials: Thomas C. Weiss is a researcher and editor for Disabled World. Thomas attended college and university courses earning a Masters, Bachelors and two Associate degrees, as well as pursing Disability Studies. As a CNA Thomas has providing care for people with all forms of disabilities. Explore Thomas' complete biography for comprehensive insights into his background, expertise, and accomplishments.