Will you eventually get alzheimer's disease if you get old enough, even if you don't have any of the genes?

Unknown. There is no known answer to this question. We do know that there are people over the age of 100 who do not have alzheimers disease. We also know that there are people who have no clinical evidence of alzheimers at their death but who do have brain changes suggesting that they do have the illness.
Not Really. Like many medical conditions, alzheimer's disease (ad) is the result of the interplay between genes & behavior. You can have good genes despite bad behaviors or vice-versa. Nonetheless, there are some things that you can control such as diet, exercise, & mental activity. We believe that new behaviors are especially helpful. At 85 the chances are 50% that you will have ad.