Apr 122017
 

Perhaps your grandmother had Alzheimer’s disease; maybe your mom or dad is currently living with the disease. You may be concerned that you are seeing signs of the disease in yourself or a loved one. Whatever the situation, if your family has been touched by Alzheimer’s, it is natural to be curious if a genetic test is valuable in predicting the likelihood of developing the disease. Although the cause of Alzheimer’s is still unknown, scientists have identified a number of genes that impact your risk of developing the disease.

On Thursday, April 6, the U.S. Food and Drug Administration (FDA) announced that they have approved at-home genetic testing through the 23andMe Personal Genome Service Genetic Health Risk (GHR) test, which tests for genes associated with risk of 10 diseases or conditions, including late-onset Alzheimer’s. People will be able to send 23andMe a saliva sample and receive their genetic data back through the mail.

We spoke with Keith Fargo, Ph.D., Director of Scientific Programs and Outreach at the Alzheimer’s Association, about what you need to know about this type of testing – and what the results tell (and don’t tell) you.

Two categories of genes influence whether a person develops a disease: risk genes and deterministic genes. Alzheimer’s genes have been found in both categories. Can you explain the difference between these types of genes?

Risk genes increase the likelihood of developing a disease, but do not guarantee it will happen. Deterministic genes directly cause a disease; they guarantee that anyone who inherits one will develop the disorder.

23andMe says their genetic test evaluates more than 500,000 genes and gene variants. Regarding Alzheimer’s, it evaluates whether you have the APOE-e4 Alzheimer’s risk gene. It was the first Alzheimer’s risk gene identified and remains the one with strongest impact. Having one copy of the APOE-e4 gene increases your risk – having two copies increases it more – but it is hard to say exactly how much for any individual.

There are two other variations of APOE, known as e2 and e3. The e3 variation is relatively neutral and the e2 variation may provide some protection against Alzheimer’s dementia. The newly approved test does not evaluate for these variants. Plus, there are nearly 30 other genes that have been identified to also affect risk of late-onset Alzheimer’s, but (a) those genes don’t impact risk as much as APOE-e4, and (b) this test does not evaluate for them.

There are three more genes that have misspelling in their DNA or mutations where, if you have one, it’s a virtual certainty that you will develop Alzheimer’s dementia. These are the deterministic genes. The 23andMe test does not look for these gene mutations, either.

Part of the challenge with understanding the value of the newly approved test is that many people who have APOE-e4 never experience Alzheimer’s dementia symptoms, and many who do develop the disease do not have any copies of APOE-e4.

For this reason, and because of the current lack of proven preventive strategies, the Alzheimer’s Association does not recommend genetic testing for Alzheimer’s disease for the general population. If you are concerned about Alzheimer’s disease or memory changes in yourself or a loved one, the Association encourages you to have a frank conversation about your risk with your healthcare provider.

If someone’s parent or sibling had or has Alzheimer’s, is he or she at a higher risk of developing the disease?

The fact is this: everyone is already at risk. Of people 85 and older, one third of them have Alzheimer’s dementia. And having a family history of Alzheimer’s is not necessary for someone to develop the disease.

That being said, people who have a parent, brother or sister with Alzheimer’s are more likely to develop the disease, and those who have more than one first-degree relative with the disease are at even higher risk. But, again, it is hard to say exactly how much an individual’s risk may be.

If someone is interested in having genetic testing done, what are the first steps he or she should take?

The Alzheimer’s Association suggests that you talk to a genetic counselor before deciding to take the test and, if you decide to get genetic testing for Alzheimer’s, again after you receive the results. The National Society of Genetic Counselors website provides a searchable directory to locate a counselor by location and specialty.

What are the benefits of speaking with a genetic counselor?

A genetic counselor can help you understand what the test does and does not do. He or she can help you work through making a decision that is best for you in terms of ordering the genetic testing kit. Once you get the results back, he or she can help you determine what the results really mean.

Some people think that this is a diagnostic test for Alzheimer’s, but it’s not. It is a test for the presence of one or two copies of the APOE-e4 Alzheimer’s risk gene. It’s not going to answer the question most people have, which is: “Will I get Alzheimer’s disease?” You can have two copies of APOE-e4 and never develop Alzheimer’s disease. Conversely, you can have no copies of the gene and still develop the disease.

Do you believe that taking a genetic test is a proactive step in controlling one’s health?

For some people, yes. It may give them the motivation they need to make lifestyle changes that can reduce their risk of cognitive decline as they age, and possibly even reduce their risk of dementia. In fact, there are behaviors that we should all be doing to keep our brain healthy as we age. As a starting point, the Alzheimer’s Association has research-based brain health tips that we call 10 Ways to Love Your Brain. You can find them at www.alz.org.

That said, at the Alzheimer’s Association, we are concerned that people who receive results that confirm they don’t carry APOE-e4 will assume that means they won’t develop Alzheimer’s. The truth is that these people are still at risk.

With an unsupervised at-home test, there is a real possibility of people misunderstanding their results, which could result in making misinformed decisions about their health. A genetic counselor can be helpful in making informed decisions. If you choose to take a genetic test, discuss it with a genetic counselor before and after so that you are educated about the process, the test and what the results mean. And if you are already experiencing symptoms of cognitive decline, see a healthcare professional for a full evaluation.

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Jul 062015
 

Five years ago, after being diagnosed with Alzheimer’s, my mom Sonia moved from Chicago to Missouri. She lived with my brother for a month and then with my sister for about a week. It was soon obvious that I had to take over the responsibility of being her primary caregiver. We were always inseparable, but now we are more inseparable thandaisy1 ever.

Due to a very long history of Alzheimer’s in my family, I was asked if I wanted to take part in a clinical study, which included a test to see if I carry the gene for early-onset familial Alzheimer’s.* I didn’t think twice. My brother and sister chose not to take it, but the minute it was brought to my attention, I wanted to do it. It was in my head from the beginning – what if I have Alzheimer’s and it is exposed at age 42 or 43? I am almost 40. Who is going to take care of my mother? Who is going to take care of me? I had to prepare myself.

daisy4I worked on getting all of my ducks in a row, taking all the proper measures and precautions.  I got life insurance right away so that someone would be able to take care of my mom and not have to put her in a nursing home. In addition to taking care of mom, I had to be willing to accept whether or not I will have the disease. Three-quarters of my family has passed away with Alzheimer’s. I am the only one of my siblings that wanted to be tested. I would like to think that I inspired my cousins – who are now interested in finding out if they carry the gene – as their mother was recently diagnosed as well.

As for me? The test came back positive. One day, I will have Alzheimer’s.

I don’t think of it; I simply shrug it off. I just see what my mom is going through and know I need to take care of her. In my younger years, I was a bit of a party animal – I owned a sports bar – and now my mom is my main focus in life. How can I be a caregiver to someone I love so much and not stand up for her and her needs as someone with the disease? She is what matters the most.

My typical day is very different from what it used to be. I wake up, make coffee and then wake up Mom. I often have to strip the bed and then take her to bathroom and get her into the shower. Then I brush her teeth, dress her and do her hair and makeup. I take her to work with me at my sister’s restaurant, and she is with me all day until I get off work. We often go on a walk to get some ice cream and go to the park. I end the day by taking her home and making her dinner. After she goes to bed, I go to sleep, and I do everything again the next day. It’s a whole new life.daisy3

The Alzheimer’s Association has been there for me every step of the way. I had already been on team Sonia’s Angels in the Walk to End Alzheimer’s for the past few years in support of my grandma and my mom. When I was diagnosed by my genetic counselor, I received information about grieving, counseling and caregiving from the Association. In my previous life, I had never been an activist; I was the quiet one. Now I advocate for my mom. If you wish to see a change in the world, you have to step up.

My involvement in the Dominantly Inherited Alzheimer Network (DIAN) study means that I take a variety of medications and skills tests. Although the whole group is supportive and loving, the medication is physically very painful for me. All the same, if my participation helps find a cure for someone in the future – whether it’s me or my nieces and nephews – I will take all of the pain. I try to stay positive. Everything happens for a reason, and life is too short to just mope around.

daisy2I help spread awareness because there is a stigma surrounding age and Alzheimer’s. People always tell me that I look 21 years old and can’t imagine that I could develop this disease at any time. The truth right now is that Mom has the disease; I have the gene, but I don’t have the disease yet. That is why I try not to dwell on it.

There is simply not enough money or exposure for Alzheimer’s. We have to get the word out in order to save the future for others. The more awareness we can raise, the better it is for the disease. We need to find – and fund – a cure. Alzheimer’s is currently the 6th leading cause of death; we must make strides to end it now.

 

*Younger/Early-onset Alzheimer’s caused by a genetic mutation is rare and the vast majority of early-onset and late-onset cases cannot be determined by a genetic test. Health professionals do not currently recommend routine genetic testing for Alzheimer’s disease, although testing for APOE-e4 is sometimes included as a part of research studies. For more information on Genetic testing, click here.

About the Author: Daisy Duarte, 39, is a caregiver for her mother Sonia, 59. Daisy speaks to colleges and other groups to raise awareness in the fight to end Alzheimer’s. Daisy and Sonia live in Missouri.

Learn more:

TrialMatch
Genetics and Alzheimer’s
Caregiver Center

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