Why DNA Doesn’t Always Predict Disease

May 27, 2010

When James Watson, codiscoverer of the double helix, had his genome fully sequenced in 2008, there was one piece of DNA he insisted the lab not tell him about: whether he had a genetic variant that significantly increases the chance of developing Alzheimer’s disease. Called apoE, the gene comes in three variants, of which APOE4 increases the risk of Alzheimer’s between 10- and 30-fold. Different people have different feelings about learning what lies in their medical future, especially if it is something for which there is neither cure nor treatment. (House got good mileage out of this dilemma when Thirteen, played by Olivia Wilde, decided to find out whether she carries the gene for the inevitably fatal, incurable Huntington’s disease. She does.) If studies coming out over the last few months are any indication, however, most of us can postpone making this difficult decision: the revolution in using DNA to read people’s medical future is turning out to be more hype than hope. (Newsweek)