For the first decade of his life, every doctor who saw Jack DeWitt inevitably zeroed in on the harrowing circumstances of his premature birth.

Delivered by emergency Caesarean section in December 1999, doctors universally ascribed his developmental problems to his being born six weeks early, said his mother, Ruth DeWitt. “It always came back to that.”

When Jack’s walking became odd at age 5, doctors chalked it up to a mild form of cerebral palsy that can occur in children born too soon. “We were okay with it,” his mother said, because mild cerebral palsy would not “affect the length of his life or his enjoyment of it.”

Jack’s parents were also reassured by his ability to catch up; with help, he mastered various skills: jumping, walking and writing in cursive.

But by age 10, when his ability to walk badly deteriorated, a reevaluation by his doctors resulted in a very different diagnosis and prognosis.

Read More: Medical Mysteries: Cerebral palsy proves not to be the cause of boy’s decline