Two research groups located in Wales and France discovered genes linked to late-onset Alzheimer's disease.  Late-onset Alzheimer's means developing the disease at age 60 years
and over.

The three genes are clusterin, complement receptor 1 (CR1) and PICALM and they indicate a high risk for getting the disease.  These three genes that were identified can account for the genetic tie to developing late onset Alzheimer's. The presence of these genes does not mean that the person will definitely get Alzheimer's disease.  In fact, most healthy people have these genes present in their DNA but in a different version.  These genes come in different forms and it's their interaction with other genes in the body as well as the individual's environment may determine how powerfully they contribute to the risk of Alzheimer's.  "While discovery of the three new genes contributes a wealth of knowledge about Alzheimer's, they leave considerable room for the discovery of other key genes - experts agree that there are likely legions of genes that may play a role in the development of any given diseases - and ultimately, new treatments", (Time Magazine, Alice Park).