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Special Populations Affected By Alzheimer’s Disease

Within the patient population of Alzheimer’s disease, there are certain populations that may warrant extra attention or research, or are worth noting and discussing. This includes early-onset Alzheimer’s disease and late-onset Alzheimer’s disease with the APOE4 gene. Sometimes early-onset Alzheimer’s is also called younger-onset Alzheimer’s disease. Both subsets of Alzheimer’s carry with them special considerations that are worthy of discussion.

Early-onset Alzheimer’s disease

Early-onset, or younger-onset, Alzheimer’s disease is when Alzheimer’s is diagnosed in someone younger than 65 years old.1 This occurs in nearly 5% of those with Alzheimer’s disease, which means about 200,000 Americans have early-onset Alzheimer’s.1 Doctors aren’t typically looking for symptoms of Alzheimer’s disease in younger patients and so there might be a delay in an accurate diagnosis: symptoms may be assumed to be a result of stress or another ailment. In most instances of early-onset Alzheimer’s, the exact cause is unknown; however, there are rare cases where rare genes are passed on and symptoms occur in people in their 30s, 40s, and 50s. In these instances, this is called familial Alzheimer’s disease (FAD), and there is often a significant family history of Alzheimer’s with multiple people in multiple generations affected.1

If you’re younger and are concerned that your symptoms might be a result of early-onset Alzheimer’s disease, tell your doctor about your concerns. Ask for a comprehensive medical exam with a doctor who specializes in Alzheimer’s disease. They might do cognitive testing or brain imaging, if need be. Ruling out other possibilities is helpful since there is no one definitive test for Alzheimer’s disease. Knowing the underlying cause of your symptoms will determine the appropriate treatment.

Late-onset Alzheimer’s disease

Most people with Alzheimer’s disease have late-onset Alzheimer’s, which means they are diagnosed in their mid-60s or later. There is not one specific gene that causes the late-onset type of Alzheimer’s disease, but having the APOE4 gene on chromosome 19 does increase one’s risk of developing late-onset Alzheimer’s disease.2 An individual can have zero, one, or two APOE4 genes. Having more APOE4 genes increases your risk of developing Alzheimer’s.2 However, having this gene does not mean you definitely will develop the disease; it just increases your risk for the disease. Genetic testing is typically not recommended because all this gene does is signify a possible risk factor. It is believed that so many other influences – health behaviors, lifestyle, and other potentially unknown variables – are at play in whether an individual with the APOE4 gene develops Alzheimer’s disease.

Scientists are studying the genetic components of both early-onset Alzheimer’s disease and late-onset Alzheimer’s disease, hoping to find information that will better allow the prediction of who gets the disease, as well as potential treatments for stopping the disease. If you fall into either one of these populations, talk with your doctor about potential trials you can be a part of that might help further research, or trials focusing on genetic treatments that could help manage symptoms of your disease.

Written by: Jaime Rochelle Herndon | Last reviewed: June 2019
  1. Alzheimer’s Association. Younger/Early Onset. 2019. https://www.alz.org/alzheimers-dementia/what-is-alzheimers/younger-early-onset Accessed April 8, 2019.
  2. National Institute on Aging. Alzheimer’s Disease Genetics Fact Sheet. 2015. https://www.nia.nih.gov/health/alzheimers-disease-genetics-fact-sheet Accessed April 8, 2019.