Recent research indicates that people with two copies of the APOE4 gene are almost certain to exhibit symptoms of the neurological disease by their mid-60s.

In a new paper in Nature Medicine, an international team of neurologists makes the compelling case that people with two copies of a gene called APOE4 aren’t just at risk of Alzheimer’s — they have a distinct form of the disease and are almost certain to develop its telltale brain plaques by age 65.