Doctors have used an experimental gene therapy to develop a possible treatment for children born with X-linked severe combined immunodeficiency disorder, also known as "bubble boy" disease.
Jayceon Golden, 2, is a pretty typical toddler. He likes to play ball, and peek-a-boo.
When he was born, his aunt, who takes care of him, thought moments like that might never be possible.
Jayceon was born without a functioning immune system.
"What kind of life would that be? Nobody touch him, he can't have friends. He can't go to birthday parties, he can't swim. How am I going to tell him as he gets older he can't go outside?" said Dannie Hawkins.
Current treatment requires children with the diagnosis to undergo a bone marrow transplant and a lifetime of immune boosting maintenance with antibiotics and other drugs.
But there's new hope for children like Jayceon, because of a new experimental gene therapy treatment developed at St. Jude Children's Research Hospital in Memphis, Tennessee.
Researchers harvest the stem cells of kids like Jayceon, and insert those cells with healthy genes. Those cells are then infused back into the children, where they repopulate and boost the immune system.
Dr. Mort Cowan oversaw Jayceon's treatment at the University of California, San Francisco. He said Jayceon was able to start to live a relatively normal life about four months after the infusion.
"I don't use the cure word very often for these patients, but I have to tell you I truly believe we've cured Jayceon of his severe combined immunodeficiency disease," said Dr. Cowan.
Jayceon is one of eight children who have been treated with this experimental therapy. They are all doing well.