Stefansson and his cardiovascular research team have worked with collaborators around the world to discover common and rare variants associated with risk of atrial fibrillation, coronary artery disease (CAD), stroke, peripheral artery disease, sick sinus syndrome, and aortic and intracranial aneurysm. Among their noteworthy recent discoveries is a rare variant in the ASGR1 gene that confers substantial protection from coronary artery disease, the leading cause of death in the developed world.  This finding is being used in drug discovery and development at Amgen. Another very large study, analyzing clinical and whole-genome sequence data from some 300,000 people, found more than a dozen relatively rare variants corresponding to elevated cholesterol levels. However the genetic links to CAD risk provided a new view of how cholesterol is linked to heart disease. They reported that measuring non-HDL cholesterol (so-called 'good cholesterol') better captures risk than measuring LDL (or 'bad') cholesterol, which is current standard practice.