In the study, the researchers looked at the brains of eight patients who, as children, received a medical procedure that was later found to transmit prions. They all died of CJD between the ages of 36 and 51. And yet the researchers were surprised to find that six of their brains contained the protein amyloid beta, thought to be a driver of Alzheimer's disease. In fact, four patients had "quite substantial Alzheimer-like pathology," says John Collinge, one of the authors of the study said in a press conference. "In that age group you don't really see this sort of pathology; it's only really seen in elderly individuals unless you have a genetic predisposition to it, and none of these patients did."