Tennis champion Venus Williams abruptly pulled out of the U.S. Open tennis tournament on Wednesday, claiming it was because of an autoimmune disease she has recently been diagnosed with.

“I’m really disappointed to have to withdraw from this year’s U.S. Open,” Williams said in a statement from Flushing Meadows, New York.  She then revealed the shocking news about her medical illness: “I have recently been diagnosed with Sjögren’s Syndrome, an autoimmune disease which is an ongoing medical condition that affects my energy level and causes fatigue and join pain.”

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The 31-year-old is a seven-time Grand Slam champion, but she has struggled with health problems this year.  She has only played four tournaments so far and a viral illness and abdominal injury kept her sidelined most of the year.

Serena Williams turned up the Miami heat as she hit the beach in a bikini and RadarOnline.com has the photos.

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The tennis ace hasn't played competitively since July 2010 due to a series of health problems but she looked fighting fit once more as she soaked up the sun Saturday afternoon.

The 13-time Grand Slam winner is anxious to get back to her old competitive self and earlier this week tweeted that she's back on the court, working at her game.

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