Autoimmune Disease Sidelines Venus Williams

Venus Williams finally has a name for her biggest foe in tennis: Sjogren's syndrome. The 31-year-old abruptly withdrew from the US Open today, announcing that she has been diagnosed with Sjogren's, an autoimmune disease that causes fatigue and joint pain and can lead to longer-term problems. (More details on the disease, which affects 4 million Americans, here.) Williams has been plagued with what she previously described as an "energy-sucking" illness for some time now, reports USA Today.

Still, she returned to action Monday with a victory and seemed upbeat about her health until today's surprise announcement. "I enjoyed playing my first match here and wish I could continue but right now I am unable to," she said. "I am thankful I finally have a diagnosis and am now focused on getting better and returning to the court soon." A Bleacher Report blogger is confident she'll be back. (More Venus Williams stories.)