Scientists whose laboratory studies first suggested that an FDA-approved drug, losartan, might prevent the potentially deadly enlargement of the aorta caused by Marfan syndrome now have an even clearer picture of the cellular signals that contribute to the disease. While a clinical trial testing losartan’s ability to slow progression of aneurysm in people with Marfan syndrome continues, ongoing research is generating data that will help guide treatment decisions and inform efforts to develop alternate therapies.