APOE e4 e4 predictor

Alzheimer's, cardiovascular, and other chronic diseases; biomarkers, lifestyle, supplements, drugs, and health care.
Post Reply
steve52
New User
New User
Posts: 2
Joined: Sun Sep 23, 2018 5:45 pm

APOE e4 e4 predictor

Post by steve52 »

My mother died of alzheimer's. My sibling is double e4 per genetic testing. How likely is it that I am also double e4 ? Thank you.
Jennifer
Contributor
Contributor
Posts: 18
Joined: Fri Nov 17, 2017 6:47 am

Re: APOE e4 e4 predictor

Post by Jennifer »

Assuming your sibling is a full sibling, then at best, the punnett square would predict 25% chance of double e4. You know that your mother had at least one e4, because she gave it to your sibling. So at best, your mother is a e3/e4. Same for your father. He is at best a e3/e4 because he gave the other e4 to your sibling. Assuming that both of your parents are e3/e4, then you have a 25% of e3/e3, 50% of e3/e4, and 25% e4/e4. If your mother is e4/e4, and your father is e3/e4, then you have a 50% chance of being e4/e4 and a 50% chance of being an e3/e4.
NF52
Support Team
Support Team
Posts: 2772
Joined: Tue Oct 25, 2016 9:41 am
Location: Eastern U.S.

Re: APOE e4 e4 predictor

Post by NF52 »

steve52 wrote:My mother died of alzheimer's. My sibling is double e4 per genetic testing. How likely is it that I am also double e4 ? Thank you.
Welcome steve52!

If your "52" signals that you were born in 1952, then you and I (and my husband and lots of others) picked a great year to be born and can enjoy being 66! We have some great mathematicians on the forum, but as a 4/4, I'll try to answer you this way:

Your sibling is ApoE 4/4. That means she (or he) got one ApoE 4 from each parent.
That means each parent had at least one ApoE 4. So your mom and dad each can be assumed to have had ApoE 2/4, 3/3 or 4/4.
Those could combine with each pregnancy this way, with combinations showing Mom's allele first, then Dad's:

Mom: ApoE 2/4 + Dad: ApoE 2/4= ApoE 2/2, 2/4, 4/2, 4/4
Mom: ApoE 3/4 + Dad: ApoE 2/4= ApoE 3/2, 3/4, 4/2, 4/4
Mom: ApoE 4/4 + Dad: ApoE 2/4 = ApoE 4/2, 4/4, 4/2, 4/4

Mom: ApoE 2/4 + Dad: ApoE 3/4 = ApoE 2/3, 2/4, 4/3, 4/4
Mom: ApoE 3/4 + Dad ApoE 3/4 = ApoE 3/3, 3/4, 4/3, 4/4
Mom: ApoE 4/4 + Dad ApoE 3/4 = ApoE 4/3, 4/4, 4/3, 4/4

Mom: ApoE 2/4 + Dad ApoE 4/4 = ApoE 2/4, 2/4, 4/4. 4/4
Mom: ApoE 3/4 + Dad ApoE 4/4 = ApoE 3/4, 3/4, 4/4, 4/4
Mom: ApoE 4/4 + Dad ApoE 4/4 = ApoE 4/4, 4/4, 4/4, 4/4

So, if I did this correctly, your parents could have had 9 possible combinations of ApoE 2, 3 and 4 between them. Some, like ApoE 3/4, are much more common than ApoE 2/4 or 4/4, which only about 2-5% of the population has. That gives 36 possible combinations, of which 16, or 44% are ApoE 4/4.

But that doesn't really tell you much, since 5 of those possible 9 combinations are based on the 2% chance that one or both parents had ApoE 4/4. As Jennifer said, if you assume that your parents were among the 20% or so of people with Northern European ancestry who have only one ApoE 4 allele and were both ApoE 3/4, that would reduce your chances of having ApoE4 to only 25%, since each pregnancy could end up with ApoE 3/3, 3/4, 4/3 or 4/4.

If you're wondering what your Apoe E status is, you might want to do is check out theThinking about Testing? and the Primer, written by a physician member as a great intro to all these ApoE 4.

It's helpful to remember that ApoE 4/4 is not a sentence of inevitable Alzheimer's! Currently, age is the greatest risk factor for any kind of dementia, with about 1/3 of people over 65 having some kind of mild cognitive impairment, Parkinson's, Alzheimer's, or other dementia. People with ApoE 4/4 who are currently 60-75 are predicted to have statistically a wide range of possible Mild Cognitive Impairment or dementia by age 85--somewhere between 30% and 55% risk. As someone who is a 4/4, I am not naive about my risks, but also believe that I can control how I try to reduce it and plan for a long, happy life. FYI, the Primer has great suggestions on things that would benefit everyone, including getting a good night's sleep, treating high blood pressure and sleep apnea, using alcohol in moderation, avoiding sugars and processed foods.

Hope this helps, Steve!
4/4 and still an optimist!
steve52
New User
New User
Posts: 2
Joined: Sun Sep 23, 2018 5:45 pm

Re: APOE e4 e4 predictor

Post by steve52 »

Hello Jennifer and NF52,

Many thanks to you both for your answers to my question. I am looking forward to being part of this group. Much to learn.
Steve52
User avatar
srbogert
Contributor
Contributor
Posts: 67
Joined: Mon Aug 06, 2018 12:16 pm
Contact:

Re: APOE e4 e4 predictor

Post by srbogert »

Welcome to the group Steve52
Jennifer and NF52 have already given you some great answers to your question about probability. I just want to reinforce NF52's point that this is much more than just a genetic numbers game. Your choices regarding diet and lifestyle and other health factors will have a huge impact on your ability to avoid cognitive decline. If you've ever played poker you know that the hand you are dealt is only half the story - how you play the hand is key. This is the same sort of thing - Genetics is not destiny.

NF52 recommended that you read the Primer as a next step. If you want more information, you can look through the site's WIKI or go to Dr Bredeson's book "The End of Alzheimer's". As you navigate the site, doing searches and making posts, you will probably find the How To Guide helpful.

Welcome aboard! Feel free to share your questions and experience.
Functional Medicine Certified Health Coach
National Board Certified Health & Wellness Coach
Post Reply