There was a movie based on the book as well. The book involves Harvard, Brigham Young, and all of the people who do the genetic testing. Anyone who has a relative that has been diagnosed with Alzheimer's Disease should be genetically tested to see if they carry the gene so that they can prepare for their own battle, or if they have passed it on to their children, or grandchildren so that they know what to look for in the future.
I think the issue of genetic testing is pretty controversial. Though your risks may be higher if you have certain genes, there are other factors as well, so, it's not a given that you will get it. So, I'm not sure I would want that worry, if it's not certain and if it is certain.....I don't know. It's a personal decision I suppose.