The scope of gene testing is still pretty limited.
While scientists are doing amazing work unraveling the genome's mysteries, there's still more we *don't* know about genetics and Alzheimer's than we do know. So far, you can find out conclusively if you have the gene that indicates a kind of early-onset Alzheimer's (striking about ages 30 to 60) that runs in families. But it's a rare form of Alzheimer's, and doesn't apply in my relatives' case.
More useful for those of us dealing with late-onset Alzheimer's (after age 65) is testing that can tell you which variants of the APOE gene (explained here) you carry, as well as some other influencing genes. About one quarter of Americans carry the highest-risk form of APOE, called APOE-4. But not all of them go on to develop the disease.
It's not yet known whether heredity or environment is the bigger culprit.
Although we know a few genes that affect Alzheimer's, we don't know yet what activates them. Knowing you were born with a high risk or low risk of Alzheimer's isn't the same as knowing your fate. Since the cause of Alzheimer's is still unclear, it could turn out that something about lifestyle is ultimately to blame, regardless of genetic make-up. (Although I sort of doubt the smoking gun will be sunscreen, a theory that made headlines this week after two UK researchers received a grant to study it. I don't know too many octogenarians who slathered on sunscreen in their youth.)
Maybe another way of saying this one is: Knowledge is power, but uncertainty is at best irrelevant and at worst needlessly scary.
There are increasingly solid prevention steps everyone should try regardless of genetic risk.
Whatever genetic test results would tell me, I'd be crazy not to pay attention to the louder voice of increasingly compelling research that links obesity, high blood pressure, poor cardiovascular health, and diabetes to Alzheimer's. Clearly, these are health situations to work to avoid. I don't need a gene test to do that, or to avoid head injury and strive to stay intellectually engaged and socially stimulated – all factors linked with a lower risk of developing Alzheimer's.
So knowing all that...would you get tested if you were me? Do you plan to do so yourself, or have you? Take this poll and also tell me what you think. I'd really like to be persuaded, one way or the other.
