Science / Medicine : Cystic Fibrosis Clues Surface

A newly discovered cluster of genetic flaws responsible for a small fraction of cystic fibrosis cases may provide valuable clues to finding a treatment for the nation’s most common inherited fatal disease, a U.S.-Canadian research team reported last week in the British journal Nature. The four genetic defects together account for about 7% of cystic fibrosis cases in whites and 5% in American blacks.

The new research suggests that the genetic mutations lie in a region of the gene that appears to be the blueprint for a protein that binds to a chemical fuel called adenosine triphosphate or ATP, said Dr. Gary Cutting of Johns Hopkins School of Medicine, who collaborated with researchers at Toronto’s Hospital for Sick Children.

Researchers previously speculated that the cystic fibrosis gene is the blueprint for a protein that may act as a pump to carry chloride out of cells. Chloride is important for regulating cells’ water balance, and upsetting that balance may be what causes mucus in the lungs of cystic fibrosis patients to thicken, impairing breathing.

ATP is not directly involved in the transport of chloride in and out of cells, which prompts researchers to speculate that the cystic fibrosis protein may pump something other than chloride. Exactly what that substance is remains a mystery, but researchers said it could have an indirect effect on movement of chloride in the body.