No two O'Donnell children has an identical set of symptoms, but they all share one defining characteristic -- a failure to have appropriate social interactions.
All of the O'Donnell children have speech challenges, avoid eye contact and display little facial emotion.
"It's not that they can't have any expression of emotion or attachment, it's just that it's very different," Amaral said.
Today, all the children except Kiernan attend regular school; Caitlin is helped in school by an attendant. The O'Donnells say patience and a sense of humor get them through.
"We laugh," Patrick said. "We have to laugh. If we don't laugh, we wouldn't be ourselves."
And they have conviction that their children matter. "I'm very proud of what our children have accomplished," Patrick said.
With their five distinct personalities, the O'Donnell children are a unique bridge to help researchers learn more about the mysterious world of autism. And each in their own singular way, they bring love and joy to a very special family.
"We have children that are unique," Jeanette says. "We have children that fit in our family."