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Two questions about genetics and APOE status

Posted: Thu Jan 21, 2021 7:20 pm
by Mindbender
1. Awhile back I got my 23andMe data and it gave me my rs429358 reading as TT but my rs7412 shows as "- -". I believe this narrows down my APOE status possibilities as:
E2/E2
E2/E3
or E3/E3

Aside from getting my genetics tested again, is there a way I can figure out my exact status given my other known genetics provided by 23andMe?

2. I got my son's 23andMe done at the same time I got mine and he too did not get a reading on rs7412. But his rs429358 is a CT. Does that mean his father has a rs429358 of CC? Or could his father also be a CT? Concerned that my son is possibly an E3/E4 and his father could be E4/E4.

Re: Two questions about genetics and APOE status

Posted: Mon Jan 25, 2021 6:36 pm
by NF52
Mindbender wrote:1. Awhile back I got my 23andMe data and it gave me my rs429358 reading as TT but my rs7412 shows as "- -". I believe this narrows down my APOE status possibilities as:
E2/E2
E2/E3
or E3/E3

Aside from getting my genetics tested again, is there a way I can figure out my exact status given my other known genetics provided by 23andMe?

2. I got my son's 23andMe done at the same time I got mine and he too did not get a reading on rs7412. But his rs429358 is a CT. Does that mean his father has a rs429358 of CC? Or could his father also be a CT? Concerned that my son is possibly an E3/E4 and his father could be E4/E4.
Hi Mindbender!

Sorry you've had to wait for a response on this interesting question! Having used 23&me myself, along with my husband, I'm surprised that they didn't give you an answer for your rs7412, unless perhaps you only signed up for the Ancestry report and not the Health report. If the omission is for something you paid for, it may be worth contacting Customer Service and asking them if they can re-run the sample for each of you, or give you another free test.

But in the interest of trying to give you a little info, here goes:

Your rs429358 homozygous (2 copies) of TT does seem to show that you have at least one copy of the low-Alzheimer's risk ApoE 2 gene. You can see in the first column of this snpedia report that TT is always one copy of ApoE 2: https://www.snpedia.com/index.php/APOE.
So your possibilities are ApoE 2/2, 2/3 or 2/4.
Your son inherited one of your copies of rs429358 (since you have 2 copies, he would have to get one "T"). He also has one "C" from his father, which doesn't tell you anything about what his father's second copy of rs429358. With CT at r429358 he appears on the Snpedia chart to most likely be an ApoE3/4 or possibly Apoe2/4. It's impossible to say what his father's second ApoE allele is, but ApoE 4/4 is only seen in about 2% of the population. (BTW, I'm part of that lucky 2% and am doing just fine a few months shy of age 69.)

Either way, my own feeling is that this is news you and he can use. ApoE 2/4 is the profile of one of our 84 year old members, who is still enjoying life with gusto! And ApoE 3/4 is in 25% of the population of Europe and European descendants. According to a large international meta-analysis in 2017, it confers for people MY age (not your son's) a 20-25% risk of either Mild Cognitive Impairment of Alzheimer's by the age of 85, the current expected life span of someone 60+.

With decades to go for healthy habits and medical advances, this is simply information to help him live a long and happy life!

Re: Two questions about genetics and APOE status

Posted: Mon Jan 25, 2021 6:57 pm
by Mindbender
Wow, what a most helpful response! Thank you!! I will get in touch with 23andMe and ask them about that omission. They missed it for both me and my son and we did get the full product, not just ancestry.