The United States is faring well in the U.S. Open so far, with  Christina McHale hailing  a victory against France yesterday. But there was bad news for the U.S. team yesterday, as well. Venus Williams announced that she has pulled out of the tournament, due to health problems related to Sjögren’s syndrome, an autoimmune disease that causes joint pain and fatigue. Karen Crouse, a reporter for our partner,  The New York Times, discusses Sjögren’s syndrome and what this means for Williams’ career.