Early Onset Alzheimer's Disease: Facts and Information

Topic: Alzheimer's Disease
Author: Thomas C. Weiss
Published: 2010/03/14 - Updated: 2023/01/28
Contents: Summary - Definition - Introduction - Main - Related

Synopsis: Information regarding young-onset (also called early-onset) Alzheimer's, an uncommon form of dementia that affects people younger than age 65. Alzheimer's disease usually starts with subtle and poorly recognized symptoms, such as memory failure. Over the years, the person's memory loss slowly becomes increasingly severe, eventually incapacitating. A diagnosis of early-onset Alzheimer's disease can be obtained in families with multiple members 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.

Defining Alzheimer's Disease (AD)

Alzheimer's Disease (AD): Alzheimer's disease (AD) is characterized by adult-onset progressive dementia that is associated with beta-amyloid plaque formation, cerebral cortical atrophy, and intraneuronal neurofibrillary tangles. AD commonly starts with subtle memory failures and becomes more severe, eventually incapacitating. Additional findings that commonly include poor judgment, confusion, agitation, language disturbance, hallucinations, withdrawal, Parkinsonian features, seizure activity, myoclonus, increased muscle tone, mutism, and incontinence. Familial AD characterizes families with more than one person with AD and typically implies multiple persons who are affected across more than one generation in the family. Early-onset familial AD refers to families where the disease's onset consistently occurs before the age of sixty to sixty-five years and many times before the age of fifty-five. A minimal number of people with Alzheimer's disease have the early-onset form. Many of them are in their 40s and 50s when the disease takes hold.

Introduction

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 Digest

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 Nursing Assistant Thomas has assisted people from a variety of racial, religious, gender, class, and age groups by providing care for people with all forms of disabilities from Multiple Sclerosis to Parkinson's; para and quadriplegia to Spina Bifida. Explore Thomas' complete biography for comprehensive insights into his background, expertise, and accomplishments.

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Cite This Page (APA): Weiss, T. C. (2010, March 14 - Last revised: 2023, January 28). Early Onset Alzheimer's Disease: Facts and Information. Disabled World. Retrieved September 18, 2024 from www.disabled-world.com/health/aging/alzheimers/ad.php

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