Genetic risk of Alzheimer's has gender bias
Carrying a copy of the "Alzheimer's gene" doesn't significantly raise a man's risk of developing the disease.
The gene does increase a woman's risk, but women with one copy of the gene were as likely to develop the disease as men with no copies. The study – along with work suggesting that the gene is associated with educational achievement in young people – highlights how much remains to be done to untangle the genetics of Alzheimer's.
In 1993, it was discovered that people with Alzheimer's were more likely to carry a variant of the APOE gene called APOE4. Carrying one copy of APOE4 can increase the risk of developing Alzheimer's four-fold, while two copies can lead to a 10-fold increase in risk. Perhaps it's more complicated than that, says Michael Greicius at Stanford University in California. "There is no question that APOE4 is a potent genetic risk factor for Alzheimer's," he says. "[But] it appears from our study to vary strongly as a function of sex."
