"Amy and the Orphans," featuring an actress with Down syndrome, is an astonishing play that is likely to alter your pre-conceptions about so-called mental handicaps. The casting alone of the amazing Jamie Brewer in the title role certainly makes the point. But Lindsey Ferrentino's touching drama delves even deeper, questioning the bonds of family and the limits of love.

Inspired by the playwright's aunt, born with Down syndrome, the story is a deeply personal one. But more than a tribute to Aunt Amy, the play is a highly polished work that deals with the complex and difficult emotions surrounding the arrival of a baby with Down syndrome.

Alternating back and forth in time, we meet the grown-up siblings and the parents who struggle mightily over Amy's care and treatment. With their marriage on the brink, they decide to send infant Amy away to state-run facilities and she eventually settles into a group home on Long Island where a brash and devoted caregiver provides the stability Amy never knew at home.

The play begins as the older siblings fly in for their father's funeral. Guilt-ridden, they pick up Amy and the caregiver for the long drive to bury their dad in Montauk.

If it all sounds just too grim, there is actually much humor in the play — the organic kind — and director Scott Ellis strikes the ideal balance between pathos and levity.

The performances are all first-rate. Vanessa Aspillaga provides much of the comic relief as a motormouth injecting agita into the already tension-filled road trip. She comes dangerously close to hijacking the play, but thankfully Deborah Monk and Mark Blum as the angst-ridden siblings are the perfect foils. And Diane Davis and Josh McDermitt evoke the fraught impulses of young parents with a disabled child.

But it's Brewer, impeccable as the movie-loving Amy, who steals the spotlight and our hearts. She is an amazing actress able to hold her own opposite the consummate pros. And take note when her understudy Edward Barbanell goes on, the play's title is changed to "Andy and the Orphans."

Just consider the cleverness of the play's title. Amy is the only one of the siblings who seems truly fulfilled and at peace. The other two can barely cope as orphans. By the end, it begs the question: Who's the disabled one in that bunch?