LOS ANGELES (KABC) -- A first-of-its-kind gene therapy was just approved to treat Duchenne muscular dystrophy, a devastating condition affecting roughly 1 out of 3,500 to 5,000 boys.
The game-changing treatment had a huge impact on one local family.
As a baby, 4-year-old Thomas Kargar's eyes were captivating, but as he got older, something else caught his parents' attention.
"He was behind but according to the pediatrician, because he's a boy, they're slower," said Zac Kargar, Thomas' father.
When Kargar and his wife Nicole Orellana became pregnant with their second child Charlotte, they discovered Orellana was a carrier for Duchenne muscular dystrophy, a fatal and rare degenerative muscular disease affecting mostly boys.
"With time, the patients will eventually stop walking. It will affect their heart, it will affect their ability to breathe, to eat, and eventually they die prematurely," said Dr. Leigh Maria Ramos-Platt, program director for Children's Hospital Los Angeles Multi-disciplinary Neuromuscular Program.
Because she is a girl, Charlotte would be spared, but it was hard to believe this would be Thomas' future.
"Denial. Yeah it was just denial, for me at least," said Kargar.
Finding out about Thomas having Duchenne when they did was divine timing for the Kargar family. It allowed them to be part of a clinical trial in Sacramento.
Thomas was between 4 and 5, the age needed to qualify for a genetic therapy called Elevidys. The drug recently received FDA approval.
"Because there's a defective gene, we give the patients a replacement gene. We infect them with a better gene to produce a protein that they are missing to hopefully improve their strength, keep them walking and help them stay healthier," said Ramos-Platt.
The one-time infusion completely changed Thomas' trajectory.
"He jumped for the first time and he's never been able to jump in his life," said Orellana.
"It was a big difference to see. He wasn't able to go up and down stairs as well. Now he can do it," said Kargar.
Ramos-Platt hopes for a bright future for Thomas.
"I'm hoping that he is going to finish high school, go to college if he wants to. If he wants to get married and have kids, I'm hoping for that too," she said.
It's not a cure, but doctors see it as a very important breakthrough. And since the FDA requires rigorous hospital protocols, it could be several months before eligible patients can be treated.
The Kargars said their hope is that others who qualify get the same chance as Thomas.
"Gene therapy is just something remarkable," said Kargar.