Venus Williams withdrew from the U.S. Open before her second-round match Wednesday, citing an autoimmune disease diagnosis.
"I have been recently diagnosed with Sjögren's syndrome, an autoimmune disease which is an ongoing medical condition that affects my energy level and causes fatigue and joint pain," the two-time U.S. Open winner said in a statement.
"I enjoyed playing my first match here and wish I could continue but right now I am unable to. I am thankful I finally have a diagnosis and am now focused on getting better and returning to the court soon."
Williams, 31, was scheduled to play Sabine Lisicki on Wednesday at New York's Arthur Ashe stadium, according to SI.com. She advanced to the second round after defeating Vesna Dolonts on Monday, earning almost as much attention for her outfit as her game.
Sjögren's syndrome is a disease that is sometimes linked to rheumatic problems such as rheumatoid arthritis, according to the U.S. National Library of Medicine. It causes dryness in the mouth and eyes and may also affect joints, lungs, kidneys, blood vessels, digestive organs and nerves.
Most people who get Sjögren's syndrome are older than 40. Nine of 10 are women.