The toddler's babbling has turned into a vocabulary of about 30 words. He climbs stairs while standing upright – no hands and no knees, mom.

A toy car elicits an exclamation of "Car, car!" and guttural vrooming sounds. Then it gets pushed around the floor.

It's typical behavior for that age, and that's what makes it noteworthy. Noah Hinson showed no signs of autism spectrum disorder in a June assessment – news that his parents, Kristin and Neal, couldn't wait to share with me.

"He's just a different kid," Kristin said. "In the last week, he's really taken off."

Noah and his brothers were the subject of a story I wrote in May on the impact of autism on families and the therapies being used to overcome it at UC Davis' MIND Institute.

Noah, now 18 months old, began exhibiting symptoms of autism spectrum disorder at the age of 9 months. His brothers Justin, 7, and Simon, 4, had been diagnosed with it. Their sister, Millie, is a typically developing 10-year-old.

Noah's apparent transformation didn't happen overnight. He and Kristin completed an early-intervention study at the MIND Institute this spring, and they have been participating in follow-up sessions with doctors there to reinforce the lessons that have helped coax Noah out of the shadow of autism.

Given the family history, Noah also was enrolled in another study at the MIND Institute, the Infant Sibling Study, which tracks infants with either an older sibling with autism or an older sibling who is typically developing, in an effort to understand autism in infancy.

And it was at a blind evaluation for that study when Kristin got the news she and Neal had longed to hear: Noah was "developmentally typical across the board."

"At first, I kind of didn't believe (the researcher)," Hinson said. "I was waiting for the catch."

There was none.

"It was just this validation," Kristin said. "Finally, someone said he's doing amazing in all these areas."

Yet it doesn't mean her work is done.

"Because there's a long onset period in autism – the first three years of life – that's one reason for us to be optimistic but continue to be watchful," said Sally Rogers, professor of psychiatry and behavioral sciences at the MIND Institute.

Rogers, the principal investigator for the Infant Start study, explained that siblings of children with autism spectrum disorders seem to have more unstable patterns during the onset period than those with typically developing siblings.

Noah's prognosis, however, is hopeful in terms of the Infant Start study's success rate. He is the second of three participants who have shown no symptoms at 18 months old.

"We're pretty delighted," Rogers said. "If we can continue at that level and these children continue to do as well as they're doing now, that would reflect the prevention of the full development of autism from children who are highly symptomatic at 12 months old."

Kristin said she plans to continue working with Noah using techniques she learned while participating in the study, which have become second nature to her and her husband. That's even more important now that the family has moved to Vienna, Va., more than 2,700 miles from the MIND Institute.

"Her work's not done, but she has the tools available to use them on an ongoing basis," said Laurie Vismara, an educational psychologist who worked with Noah and Kristin for the early intervention study.

It's not just the tools that are working, however. It's the parents' investment in their children's success. Parents take tasks as mundane as changing a diaper and turn them into chances to work on eye contact and language skills. It's relentless homework.

"It's been very encouraging that both parents and children can learn from this model, that it can happen so easily," Vismara said. "There are no special tricks being done. It's really just positive parenting practices and using natural instincts and new expectations to help their children learn."

Kristin understands her work isn't done, but she's hopeful.

"I can just be his mom and love all the things he's doing and not spend time searching for all the best programs for him," she said. "He doesn't need anything for now – except me."

The Hinsons celebrated Noah's success – in many ways, a victory for Kristin – in their minivan, their kids chattering happily in the backseat.

"We went through the drive-through and smiled at each other and took a deep breath," Neal Hinson said.

Then they exhaled.

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