Tennis great Monica Seles is speaking out about her battle with myasthenia gravis, a rare autoimmune disease that weakens muscles. The 51-year-old, who won nine Grand Slam titles and was inducted into the International Tennis Hall of Fame,

Nine-time Grand Slam champion Monica Seles is battling a new challenge: a neuromuscular autoimmune disease called myasthenia gravis. The 51-year-old Seles is going public about the condition she was diagnosed with three years ago.