Alzheimer's gene sharpens young minds

Duke Han, an assistant professor of neuropsychology at Chicago's Rush University, has been researching Alzheimer's disease for years but even for him, the results were unexpected.

"I thought I actually made some sort of major mistake so I went back and did the analyses over and over again, just because I was sure that it should have been the opposite," he said.

Professor Han's work examined epsilon 4, a variant of a particular gene known as apolipoprotein E or APOE.

The epsilon 4 variant is the best established genetic risk factor for Alzheimer's disease.

Professor Han says when his team examined the link between epsilon 4 and head injuries, they were surprised by what they found.