Near the end of 2015, the playwright Lindsey Ferrentino and the actress Jamie Brewer were watching clips of Donald J. Trump, then a candidate, appearing to mock a reporter with a physical disability. They were horrified — which made their work on a new play, centered on a character with Down syndrome, all the more significant.
“From that point forward, the play took on a new meaning for me,” Ms. Ferrentino said.
“Big time,” Ms. Brewer added.
“Watching you watch that video, seeing your reaction to it, you cried,” Ms. Ferrentino said, turning to her.
“I was emotional,” Ms. Brewer said.
The play, “Amy and the Orphans,” which opens March 1 in a Roundabout Theater Company production at the Laura Pels Theater, is a barrier-breaking show. Ms. Brewer, 33, and her understudy, Edward Barbanell, 40, are thought to be the only known performers with Down syndrome to play the lead in an Off Broadway or Broadway theater production.
The show is about three siblings who reunite after their father’s death, and the road trip that follows. Ms. Ferrentino, who debuted with the critically acclaimed play “Ugly Lies the Bone,” in 2015, was insistent that the title role be played by someone with the disability, even leaving a note in an early draft of the script: “Finding a talented actor with Down syndrome isn’t difficult. So please do it."