What Does It Mean When Everyone Can Get Their DNA Sequenced?

A middle-aged woman arrives for her annual checkup toting her 50-page DNA profile, downloaded from the web. The document warns that she has gene variants that might increase her risks for Alzheimer’s disease and breast cancer — a shock, she says, since no one in her family has had either. You’re her doctor. You’ve got 12 minutes for this appointment. What should you do? Or, more precisely, what are you legally obligated to do?