J.B.
This is such a tough question and not one that I think I could answer honestly unless faced with it. There are merits to both sides. A classmate's mother did take the brave step of being diagnosed and as a result, is participating in a groundbreaking study. I think that the altruist in me would probably go for the diagnosis so that if it were something I carried, I could participate in studies that might lead to better understanding of the disease and how to halt or reverse its progress. I think I would get some satisfaction and relief, at least early on, by knowing that I was able to do something proactive and useful about this while asymptomatic. But that's me, and it's not a reality for me. I can certainly see the "ignorance is bliss" side of this too.
If you're interested, here is an article about my classmates mom:
http://www.prevention.com/health/alzheimers-disease-and-d...