Against the odds all three Holland family children Spencer, Maddie and Lanie have a rare and deadly genetic disorder called Mucopolysaccharidosis, or MPS.
Their bodies lack an enzyme that enables them to break down sugars, which then build up in and damage their joints and organs. Most kids with MPS never live to be teenagers.
When CBS News Medical Correspondent Elizabeth Kaledin first visited the Hollands last August, only Spencer had qualified to participate in trials in which an experimental drug is used to replace the missing enzyme.
"We have seen no new symptoms since starting him on this drug three years ago," said the children's mother, Amy Holland.
Initially, the Food and Drug Administration refused to allow the girls to participate in the experiments, saying more study was needed.
Now, after being poked and prodded and subjected to test after frightening test, Lanie and Maddie have finally been accepted into a new trial at the University of North Carolina Hospitals. The girls administered the first dose themselves.
"To find a treatment is like a rebirth of that child," said Amy Holland. "It takes away the sting of the word 'terminal.'"
Lanie had to have brain surgery and Maddie's ability to walk went from wobbly to worse.
But now it's their turn. Their treatment is an intravenous drip once a week. They may be getting a placebo, but their participation in the trial guarantees them the real drug after six months. It's not a cure, but the earlier trial showed great promise.
"We saw their liver dramatically get smaller, their ability to walk or move their joints improved. They felt better," noted Dr. Joseph Muenzer.
But the numbers were too small to convince the FDA to approve the drug -- a fact that has frustrated doctors and angered parents who feel the agency should act faster in approving drugs for rare diseases.
b>"Time is critical," said Dr. Muenzer. "These children only get worse with time."
With three afflicted children, that's a factor Amy Holland is well aware of. "It has been our goal for three years to get this drug to our other two children and other children in the world who need it."
For now, one part of that goal has been met. The hope is that the results of this new experiment will convince the FDA to approve the drug to help other children for whom time is running out.