Risk and Dementia – Genetics

For some types of diseases that cause Dementia to occur, there is a genetic association for having the disease by the time an individual is 60-years of age or older. It’s a subtle distinction, but people who have the altered gene inherit the risk and not the disease itself. In fact, Dementia is not a disease, rather, it is the expression of the cognitive challenges that come about because of the changes in brain tissue, caused by a particular disease.

This post mainly focuses on Alzheimer-caused Dementia but there are many other causes, e.g., Lewy body, Vascular, Frontotemporal, et al.

On the bright side, knowing that you have an inherited risk factor gives you the opportunity to do those things known to reduce risk - maintain a healthy weight, refrain from smoking, engage in socially and intellectually satisfying activities, exercise, and eat a heart-healthy diet.

For the most part, the at-risk genes change how the body processes cholesterol and other blood lipids. Therefore, it’s not surprising to find that having high cholesterol blood levels is another risk factor associated with having Dementia later in life.

Early-onset familial Alzheimer's disease (eFAD) is inherited Dementia that affects people as young as 30 years of age. (1) Unlike traits that are observable shortly after birth, such as eye color, symptoms of eFAD do not appear until the individual is 30-years of age or somewhat older. By that time, it is likely he or she has one or more children and may have unknowingly passed the early-onset gene to them.

Fortunately, there are DNA tests that can identify the presence of the increased-risk genes as well as those that cause eFAD.

Making the decision to undergo genetic testing is difficult. Will know to make you feel anxious, relieved, or empowered? Will other family members also want to test? How might this information affect family planning for you or your adult children? Will having a positive test for a specific cause of Dementia risk factors or early-onset disease influence your employer, your career, or make it more difficult to receive health insurance? (2)

Often, people find talking with a genetic counselor can make the decision to test--or not--easier. The genetic counselor, by explaining the technical and emotional issues associated with genetic testing, can help you make a personally comfortable decision. Afterward, the genetic counselor can explain the test results to you and guide discussion about any further steps you may want to take. (2)

Find Out More About Dementia Genetics

You can find more information about genetics and genetic counseling on the following web pages: National Association of Genetic Counselors (https://findageneticcounselor.nsgc.org/) and the American Board of Genetic Counselors (https://abgc.learningbuilder.com/Search/Public/MemberRole/Verification). Both of these sites may help you find a genetic counselor located near your home.

Notes:

1.What is Early Onset Familial Alzheimer Disease? http://www.alzforum.org/early-onset-familial-ad/overview/what-early-onset-familial-alzheimer-disease-efad(accessed April 26, 2016)

2.Genetic Testing and Counseling for Early Onset Familial Alzheimer Disease, http://www.alzforum.org/early-onset-familial-ad/diagnosisgenetics/genetic-testing-and-counseling-early-onset-familial(accessed, April 26, 2016)

Want to Know Even More?

Alzheimer Disease Genetics Fact Sheet, https://www.nia.nih.gov/alzheimers/publication/alzheimers-disease-genetics-fact-sheet#genetics

(accessed, April 26, 2016)

Content Contributor: Janet Yagoda Shagam, Ph.D., is a freelance medical and science writer and the author of "An Unintended Journey: A Caregiver's Guide to Dementia.", available through Amazon. Please visit our Author's page to learn more and find this title.

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