Steven W. Bailey, an actor who has appeared on shows including "Grey's Anatomy" and "Modern Family," is opening up about a health issue he has kept hidden for years.

In a thread on X posted Jan. 2, Bailey, known for his role as bartender Joe on "Grey's Anatomy," revealed he has a rare genetic disorder known as Congenital Myasthenia Syndrome, which has been "shaping my life and my work."

"Out of career caution, diagnostic uncertainty, and being private about such things in general, I have been hiding my battle with this disease for over five years," he wrote. "Time to stop."

According to the Mayo Clinic, congenital myasthenic syndromes are a group of rare conditions "caused by a gene change that results in muscle weakness, which worsens with physical activity."

There are "many types of congenital myasthenic syndromes, depending on which gene is affected," the clinic notes, but the "most commonly affected muscles are those that control movement of the eyelids and eyes and chewing and swallowing."