Tennis legend Monica Seles is sharing her diagnosis of a chronic neuromuscular condition to help shine a spotlight on the disease for others who may be struggling with changes to their own health.
The nine-time Grand Slam champion and International Tennis Hall of Famer, who played her last professional competitive match in 2003 and officially retired from the sport in 2008, said in an interview with "Good Morning America" Tuesday that she was diagnosed three years ago with myasthenia gravis, or MG, a rare autoimmune condition.
"It was 30 years ago that I came back to the [U.S.] Open ... It was like a reset, and this was one of the reasons I decided to go public with my myasthenia gravis, because it's been a huge reset in my professional life as a tennis player, also in my personal life," Seles said, speaking about her diagnosis publicly for the first time.
Seles, who is also a spokesperson for the pharmaceutical immunology and antibody innovation company Argenx, told "GMA" that knowing her body so well as a professional athlete helped her realize that something was wrong.
"I started experiencing these symptoms of extreme leg weakness, arm weakness, double vision. So I realized, 'This is very unusual,'" she said. "Once I was diagnosed, it was like a relief, but also it was a challenge. Even coming here today -- in the old days, traveling would be a no-brainer. Now I had to get packing tips. I had to learn a new way to live with MG."
Tennis pro Danielle Collins opens up about retiring amid battle with endometriosis, rheumatoid arthritisSeles said she decided to spotlight her condition and share more information publicly to raise awareness of the disease.
"When I got diagnosed with myasthenia gravis, I had no clue what it was. I had a hard time pronouncing it," she said, noting that she hoped to use her platform "in a good way" to prompt conversations about myasthenia gravis and its symptoms, "and really just to not feel alone."
"It's been a very challenging time dealing with it," she added. "[But] knowing that there's hope out there ... and a great community ... has helped me tremendously."
She encouraged people to "advocate for yourself and know your symptoms" if they are in the process of figuring out their own health journey.
Seles, 51, also spoke to "GMA" about the current class of rising tennis stars and why she's getting excited for the final Grand Slam of the season in New York.
"I wish I had a crystal ball. I love [Coco] Gauff, the electricity she brought to the U.S. Open," Seles said. "Obviously we have a couple youngsters coming up. As a tennis fan, you know, we just want great matches and the excitement of the fans."
According to the National Institute of Neurological Disorders and Stroke, myasthenia gravis is a chronic neuromuscular disease that causes weakness in the voluntary muscles," which include those connecting a person's bones, as well as the muscles "in the face, throat, and diaphragm." Voluntary muscles "contract to move the arms and legs and are essential for breathing, swallowing and facial movements," the agency states.
MG is an autoimmune disease, a condition in which the body attacks its own healthy cells by mistake, according to NINDS.
Myasthenia gravis most commonly impacts adult women under 40, "but it can occur at any age," the NINDS website states. Symptoms can include weakness of the eye muscles, as well as muscles in the arms, legs, hands, fingers, and neck, and can also include shortness of breath, difficulty swallowing, drooping eyelids and impaired speech. Blurred or double vision may also occur, according to the agency.
Symptoms may not be recognized immediately as MG, according to NINDS, and "the degree of muscle weakness involved" may vary between individuals. In severe cases, the muscles that control breathing can be affected by a myasthenic crisis, which requires immediate medical attention and respiratory support using a breathing machine. These crises may be triggered by infection, stress, or medications and can occur in approximately 15-20% of individuals with MG.
MG is diagnosed through physical and neurological exams, blood tests and electrodiagnostic tests such as nerve stimulation tests, NINDS states. There is currently no known cure for MG, however the agency states that treatments are available to help reduce and improve muscle weakness.
ABC News' Melanie Schmitz and Dr. Jennifer Miao -- a board-certified cardiologist, critical care and interventional cardiology fellow at Yale School of Medicine/YNHH, and a fellow with the ABC News Medical Unit -- contributed to this report.
