Over the years, scientists have chipped away at the disease through incremental improvements in therapies. There are better antibiotics to prevent and treat infections and new drugs to thin out the mucus. There are also enzymes to compensate for chemicals the pancreas should make but can't.
Doctors push medications more aggressively than before and encourage patients to eat all the steak and dairy products they want. "Studies found that patients who eat higher levels of fat and more calories were actually living years longer," said Boyle.
But therapies treat symptoms, not the underlying defect that triggers them. So patients generally still see their lung function decline over time. The disease eventually overwhelms them, and they die when their lungs cannot deliver enough oxygen to the bloodstream.
At Hopkins and other specialty centers, doctors are testing a group of medications designed to make the protein work correctly. Any one of them could represent the quantum leap that doctors have so far found elusive.
"These are interesting and good times to be in cystic fibrosis research," said Dr. Craig Gerard, who treats patients at Boston Children's Hospital. "We now have drugs in development that directly target the nature of the disease."
Meanwhile, patients are reaching milestones never before thought possible.
Meg Heneberry, 24, was healthy enough to play high school sports and later competed on the women's lacrosse team at Northeastern University in Boston while studying mechanical engineering.
But six months ago, after infections sent her lung function into a downward spiral, she underwent a double lung transplant at the Boston hospital. In the process, she lost her hearing - the result of medications or a mini-stroke she might have suffered on the operating table, doctors said.
Despite these problems, she has learned to lip-read, holds down a job at an engineering firm and can take a deep breath without coughing.
"Things aren't all easier," she said in an e-mail, explaining that she still takes a battery of pills and wears a face mask in crowds to protect her lungs from germs. "It has sure been a struggle since September 11, when I received this gift of life, but it's worth it."
James Albright, 44, runs an International Baccalaureate program at a middle school in Northern Virginia. There, students barely take notice of an intravenous tube carrying medications into his arm.
