Sickle cell disease is a slow, vicious killer. Most people diagnosed with the red blood cell disorder in the US live to be between 40 and 60. But those years are a lifetime of pain, as abnormal, crescent-shaped hemoglobin stops up blood flow and deprives tissues of oxygen, causing frequent bouts of agony, along with more severe consequences like organ damage. Now, after decades of searching for a cure, researchers are announcing that, in at least one patient, they seem to have found a very promising treatment.