Monica Seles, the former tennis world No. 1 and nine-time Grand Slam champion, has publicly revealed her diagnosis with myasthenia gravis, a rare autoimmune neuromuscular disease. Seles was diagnosed three years ago and has described the condition as affecting her daily life, causing symptoms such as muscle weakness and double vision. Myasthenia gravis weakens voluntary muscles and leads to fatigue after use, impacting her ability to perform routine activities. The 51-year-old athlete first noticed symptoms while playing tennis, and she has since spoken openly about the challenges posed by this chronic illness.