Hannah Walker is one of them. She's a 14-year-old who was diagnosed two years ago with a high functioning form of Autism.
Shes undergone speech and counseling therapy that has helped her symptoms improve significantly.
"She's made extraordinary strides in her ability to interact with people," Says Hannah's mom, Poppy. "Two years ago you were looking at a different kid."
However, under a new definition proposed by the American Psychiatric Association, Hannah's form of Autism, may not exist.
People with high functioning Autism, PDD and Aspergers would likely be excluded under a much narrower range of criteria.
"Those people would not have services available under the rubric 'autism',"Explains therapist and Reach For A Difference chairman Shelby Weatherford.
The fear now surrounding the Autism community is evident when speaking with parents of children with the disorder.
"The kids that are high functioning have the best possibility of living a normal life if they have the services," Says Walker. "If that's taken away, I don't even want to know what her life would have been like."
Weatherford agrees. "It's very expensive. Maybe 30 to 40 thousand a year to get the special education and the special treatment."
A Yale School of Medicine study projects 76 percent of those diagnosed as Autistic would still qualify under the new definition.
But only 24 percent of those with Aspergers and 16 percent of those with PDD would remain.
Experts say there is still plenty of debate and research to be done, and a new definition wont be finalized until next year.
"Much of my action has been to wait and see and adapt to those situations. But with clearer boundaries and definitions we will get better research which will hopefully lead to better treatment and better outcomes," Says Weatherford.
Parents of children like Hannah fear this could be a step in the wrong direction, and hope their children still get the support they deserve
"It's such a broad spectrum of what it can look like. And its all internal. Sometimes, its only internal. And so you might not see it on the external but it's very real for her," Said Walker.