ACRISPR treatment for hereditary angioedema has just performed incredibly well in its first human trial. If the results are confirmed in larger studies, it could be the first one-and-done therapy for the painful swelling disorder. The disease: Hereditary angioedema is a rare but serious disorder that causes severe swelling in the hands, feet, face, and other parts of the body. Sometimes, these attacks can be caused by stress or physical trauma, but they often happen for no apparent reason. If untreated, it’s common for someone with hereditary angioedema to have three or more attacks every month. The attacks can last...