Hello all!
As a warning, this is a rather morbid and depressing topic, but my asking for advice on this topic is the only reason I joined the forums. Hopefully this is the correct forum for this sort of topic.
A little backstory; I'm 32 year old mtf. I've been aware of what I am since puberty, but haven't done anything about it for two reasons;
#1, I'm predisposed to Alzheimer's. My mother died in my childhood from early-onset Alzheimer's (an accelerated form that kicks in around late 30's/early 40's and degradation takes 6ish years). My father had normal Alzheimer's but passed away from sepsis (bad assisted living). There are still no confirmatory tests for Alzheimer's until symptoms are already present.
#2, my sister (whom passed away almost 2 years ago now), had put a rather large amount of pressure on me to reproduce. She wasn't aware of my gender identity issues, and she was barren. My sister was the only other living member of my family. I'm the last of my bloodline.
Now personally, I had never planned on reproducing. My family had a
bunch of genetic issues and I feel that spreading these issues would be unfair for the human race. Specifically Alzheimer's. I'm not opposed to children, and have interest in adoption. That is, assuming I don't have Alzheimer's because I
refuse to allow anyone to deal with what I experienced. This is itself a different topic and one that my partner
hates to talk about.

What did hold me back regarding my sister was a sort of family obligation to continue being her "brother" and try to support her. We were really all the other had to rely on. I knew she took after my father when it came to opinions on transgender people, and I knew she would never have accepted me if I told her I was trans.
But now she is gone so the only thing holding me back from transitioning is the fear of developing Alzheimer's, which is why I'm here.
For those who have not handled an Alzheimer's patient before, there are two important facts that you will want to understand before delving deeper into this conversation;
#1 - Alzheimer's patients loose their most recent memories/connections first. For example my mother kept mistaking me for her father, since apparently I as a teenager looked like her dad.
#2 - Alzheimer's patients (like all dementia case patients) are vulnerable to sudden and repeated environmental changes. A common example is that someones grandparent are showing signs of memory issue, so to "help" them their family may move them to assisted living. The sudden change in environment causes a massive drop in cognitive ability. In terms of Alzheimer's, changing the "normal settings" when a patient exhibiting some memory issues can cause an almost cascade of issues and years of cognitive loss within days.
How this translates to me, if I were to transition;
I'm already 32 years old. If I transition now, and end up having Alzheimer's, I may not remember some parts of this. What if I go as far as I want (including facial fem surgery), and I wake up one morning and don't recognize the person in the mirror?
If I end up with the variant that my mother has, then I could spend the next few years transitioning only to have a few years of happiness before catastrophe.
I do have a psychiatrist that I've talked with about all of this. The problem we found is that this is a rather unique situation. She is a wonderful person but even with her researching and asking peers for suggestions, there isn't enough information to work with.
At the time of this post I've been considering a partial transition, where I start hrt and maybe work on my body neck-down. This way at least I won't panic every time I look in a mirror if my memory starts slipping.
And yes I constantly keep up with Alzheimer's research. The current medications are fantastic at prolonging the memory loss, but there still isn't a confirmatory test until symptoms are present, which means that there has already been damage.
If anyone here has any ideas, feedback, or opinions, all are welcome. If there is anyone with any fragment of experience dealing with a transgender individual that is also dealing with Alzheimer's fears, please bring them to this topic.
~ Mac