Early onset Alzheimers

What It Is

Early onset Alzheimers (also called Early-Onset Alzheimer's, or Early-Onset AD) is a rare form of Alzheimer's disease in which individuals are diagnosed with the disease before age 65. Less than five percent of all Alzheimer's disease patients have this type. It is often said that it is less than two percent.

So if 4 million Americans have Alzheimer's, at least 200,000 people have the early-onset form of the disease. Early-onset Alzheimer's has been known to develop between ages 30 and 40, but that's very uncommon. It is more common to see someone in his or her 40s and 50s having the disease.

Symptoms of early-onset Alzheimer's disease are similar to those of late-onset Alzheimer's disease, but the person often is still active with work, family and social activities when the symptoms begin.

Differences Between
Early Onset and Late Onset Alzheimers

In addition to age, there are other differences between early-onset Alzheimers and the late-onset disease, including:

• More Microscopic Changes In The Brain
  Younger people who develop Alzheimer's disease tend to have more of the microscopic changes found in the brains of people with Alzheimer's disease. These changes include twisted nerve cell fibers, known as neurofibrillary tangles, and a sticky protein called beta amyloid, which forms structures called plaques.

  Plaques and tangles damage the healthy brain cells that surround them, causing the brain to waste away and shrink. Some experts believe that younger brains need to suffer more damage before the person starts to show symptoms, so this may not reflect a true difference in the nature of the disease.

• Genetic Defect
  A substantial majority of early onset Alzheimer's disease appears to be linked with a genetic defect on chromosome 14, to which late-onset Alzheimer's is not linked.
• Myoclonic Twitches
  A condition called myoclonus - muscle twitching and spasm - is more commonly seen in early-onset Alzheimer's disease than in late-onset Alzheimer's disease.
• Progression
  Some research suggests that people with early-onset Alzheimer's disease decline at a faster rate than do those with late-onset Alzheimer's disease.
• Other Feelings
  Younger people who are diagnosed with Alzheimer's disease tend to be more physically fit and active, and many still have family and career responsibilities. As a result, they tend to react differently to the disease, and may be more likely to feel powerless, frustrated and depressed.

What Causes Early Onset Alzheimers?

Early onset Familial Alzheimer's Disease (EOFAD), also called Familial Alzheimer's Disease (FAD) is an uncommon form of Alzheimer's disease that usually strikes earlier in life, defined as before the age of 65 (usually between 16 and 65 years of age) and is inherited in an autosomal dominant fashion (you only need to get the abnormal gene from one parent in order for you to inherit the disease).

It accounts for approximately half the cases of early onset Alzheimers disease. Non-familial cases of AD are referred to as "sporadic" AD, where genetic risk factors are minor or unclear.

A significant proportion of early-onset Alzheimer's is linked to three genes.
These three genes are different from the APOE gene - the gene that can increase your risk of Alzheimer's in general. But you can have the APOE gene and never develop Alzheimer's. Conversely, you can have Alzheimer's and not have the APOE gene.

The genetic path of inheritance is much stronger in early-onset Alzheimer's. If you have one of those three genes, it would be very unusual for you not to develop Alzheimer's before age 65.

Should I Get Tested For It?

If early onset Alzheimers runs in my family, should I get tested for it?

That's a personal decision that only you can make. There are pros and cons to genetic testing. Anyone who's considering it should never proceed without genetic counseling to examine these pros and cons beforehand.

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