Venus Williams announced that her withdrawal from the 2011 U.S. Open was due to her having Sjogren's Syndrome, an autoimmune disease that affects her energy levels. Williams was able to win her first-round match, but was unable to continue on Wednesday.
"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."
The Sjogren's Syndrome website says that as many as 4 million Americans live with the disease and that 9 of 10 of them are women. The disease is often characterized by dry mouth and dry eyes, and can lead to extreme fatigue and joint pain.
Williams was also forced to withdraw from the Australian Open earlier this year and did not play in any U.S. Open warmup events. She has played in just four tournaments over the past 12 months.