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Should teen football players be tested for Alzheimer's gene?

Should high school kids get a genetic test for the risk for Alzheimer’s disease before they’re allowed to play football? Two prominent scientists who study both Alzheimer’s and the traumatic brain injury suffered by some football players raise that ethically charged question in an editorial out Wednesday in the journal Science Translational Medicine.

We all carry a gene called APOE which comes in three forms. If we carry one copy of the form called E4, it triples our lifetime risk for Alzheimer’s. About 10 percent of the U.S. population falls in that category. If we have two copies of E4, the lifetime Alzheimer’s risk is 15 times greater. About 2 percent of us have that genetic makeup.

Although the connection between APOE E4 and Alzheimer’s risk has been known for years, few have suggested it as a screening tool because there’s no known way to prevent the mind-robbing disease. But, now as scientists want to test drugs as early as possible as potential methods of preventing Alzheimer’s, APOE is getting more attention, as are brain scans and other techniques that might determine who is at risk.

At the same time, scientists have been finding that football players, boxers and soldiers suffering blast injuries are more likely to develop chronic traumatic encephalopathy (CTE), the form of dementia that can follow a brain injury -- if they have one or two copies of the E4 version of APOE.

Neurologist Dr. Sam Gandy of Mt. Sinai Medical Center in New York and Alzheimer’s researcher Dr. Steven DeKosky of the University of Virginia School of Medicine, Charlottesville, conducted a poll of 49 colleagues. By a 2 to 1 decision their fellow scientists said it is not yet appropriate to test high school students, and by a 3 to 1 ratio they opposed testing military recruits. But few of the scientists dismissed the ideas out of hand.

As the evidence of a connection mounts, testing may become more of an imperative.

There are obvious, enormous ethical difficulties. Telling a 14-year-old that he or she faces an increased lifetime risk of Alzheimer’s could lead to unknowable future strains on individuals and families, as well as a lifetime of difficulty in getting health and life insurance. But if scientists learn how to intervene to prevent the Alzheimer’s, or if the evidence of increased risk from sports or on the battlefield becomes overwhelming, the question may be asked more often.

Robert Bazell is NBC's chief science and medical correspondent. Follow him on Facebook and on Twitter: @RobertBazellNBC.

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