What Is Early-Onset Alzheimer's Disease?

Reviewed by: HU Medical Review Board | Last reviewed: June 2019

Although most diagnoses of Alzheimer’s disease occur in people age 65 and older, there are younger individuals who are diagnosed with Alzheimer’s. Early-onset Alzheimer’s disease, also called younger-onset Alzheimer’s disease, is when Alzheimer’s is diagnosed in someone younger than 65.1,2 While some people diagnosed with early-onset Alzheimer’s have what’s called sporadic Alzheimer’s disease, which means there is no genetic component, there are individuals who are diagnosed with a kind of early-onset Alzheimer’s disease called familial Alzheimer’s disease (FAD). These individuals often have a family history of the disease with multiple people in their family having the disease.2 Although early-onset FAD only accounts for one percent of those with Alzheimer’s disease, it makes up 60 percent to 70 percent of early-onset Alzheimer’s disease diagnoses.3

Early-onset FAD is caused by mutations on chromosomes 21, 14, and 1.2 These mutations cause abnormal proteins to be formed, and all of the mutations are thought to be involved in the breakdown of amyloid precursor protein (APP), although the way this protein works isn’t fully understood.2 The breakdown of APP is hypothesized to created amyloid plaques, which is a defining feature of Alzheimer’s disease.2 The mutation on chromosome 21 causes an abnormal form of APP to be made, the mutation on chromosome 14 causes abnormal presenilin 1 (PSEN1) to be formed, and the mutation on chromosome 1 causes abnormal presnilin 2 (PSEN2).2 It is possible to get genetic testing for these three mutations, but it’s often not recommended.

How is early-onset Alzheimer's disease diagnosed?

It can be difficult to get an accurate diagnosis of early-onset Alzheimer’s disease because many doctors won’t be looking for it. It might take a longer time to get any necessary tests; your typical Alzheimer’s symptoms may be explained away because of stress or other factors. Medical professionals will likely be trying to rule out other diseases before they think about early-onset Alzheimer’s disease. Talk with your doctor about your symptoms and any family history of Alzheimer’s disease you might have. If need be, insist on a referral to a doctor who specializes in Alzheimer’s disease, for a comprehensive medical examination. You might also undergo cognitive testing, or be sent for brain imaging to rule out any other diseases or ailments.

If you are found to have FAD, talk with your doctor about participating in clinical trials or studies. This can help researchers learn more about the disease and aid in developing treatments and screening tools.

Resources for early-onset Alzheimer's disease

When you’re diagnosed with early-onset Alzheimer’s, there’s a good chance your life circumstances are much different than that of someone over the age of 65. You’re still working and not retired, and you may have small children. Coping with a chronic, progressive brain disease is hard no matter what, but taking these factors into consideration can make it feel even more challenging.

You might be facing disbelief from other people who aren’t aware that Alzheimer’s can be diagnosed in younger people; you might be wondering how to handle your work responsibilities and your financial future, and wonder how you will talk with your kids about the disease. There are lots of resources to help you navigate your new reality. Talk with your doctor about your concerns and your legal rights. Find a financial planner to help you with your future and your family’s future.3 Get connected with support groups, local resources, and online groups. You aren’t alone with this.

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