By combing through the DNA of more than 100,000 people, researchers at ӳý, Massachusetts General Hospital, and elsewhere have identified rare, protective genetic mutations that lower the levels of LDL cholesterol — the so-called “bad” cholesterol — in the blood. The researchers’ findings, which appear online November 12 in the reveal that these naturally occurring mutations also reduce a person’s risk of coronary heart disease by about 50 percent. Remarkably, the mutations disrupt a gene called Niemann-Pick C1-Like 1 (NPC1L1) — the molecular target of the FDA-approved drug ezetimibe, often used as a treatment for high LDL.