Orangecrush wrote:Hi! Nice to meet all of you.
...I feel safe in saying there is no family history of AD. Ive read that usually, if there is an APOE4 gene in the family, that there will generally be a family history of AD, is that true?
Is it likely my family does not have the apoe4 gene? Thank you in advance for your time.
First, let me tell you how sorry I am that you've recently lost your dad. It sounds like he lived life to the fullest, and I'm sure he was thrilled to have decades with your mom, you and other extended family members. I found that my memories of my dad, who died 33 years ago today, are still vivid and wonderful, and hope you feel that same comfort in the future.
I think you are safe in saying that there's no known family history of diagnosed Alzheimer's disease. That may mean that your family on both sides has some super "resistance" genes, whether or not they have ApoE4. Those unknown genes would have "resisted" the underlying conditions that lead to formation of amyloid plaques and tau tangles that are associated with (but may not directly cause) Alzheimer's, which is the type of dementia for which ApoE 4 is a risk factor.
It's also possible that they had strong "resiliency" genes. Autopsy studies have shown that about 30% or more of people in their 80's and 90's do have Alzheimer's pathology (plaques and/or tangles) but they don't show outward signs of the disease, possibly due to high cognitive reserve that allows them to compensate for mild problems, or high brain structural reserve (like a transportation system with a lot of alternative routes in case of congestion on a main road).
In either case, it makes it more likely that you don't have ApoE 4, but not a sure thing, since scientists have found healthy ApoE 2/4, 3/4 and 4/4 people in their 80's and 90's. And of course people with ApoE 3/3, the most common pattern, can also develop Alzheimer's and other dementias. I think what you can assume though is that you have some great genes to work with, and you can support them by using lots of strategies to minimize your mid-life risks.
Hope you're planning a bucket list that will last through your 90's!