The point of tracking down all these small mutations, Ellis explains, is to create acomprehensive blood test-on that could calculate a person’s genetic susceptibility byadding up the number of risky (and, eventually, beneficial) variables. Combined withother important factors, such as smoking, weight, blood pressure, and cholesterollevels, doctors could decide which patients need aggressive treatment, such as high-dose statins, and which ones are likely to benefit from exercise or other lifestylechanges. Some gees an already predict whose cholesterol level will respond stronglyto dietary changed, and whose won’t. Assessing risk is crucial, Ellis says becauseheart disease is often invisible. Fifty percent of men and 64 percent of women whodie of heart disease die suddenly, without experiencing any previous symptoms.