Scientists Pinpoint 105 Additional Genetic Errors That Cause Cystic Fibrosis

Of the over 1,900 errors already reported in the gene responsible for cystic fibrosis (CF), it is unclear how many of them actually contribute to the inherited disease. Now a team of researchers reports significant headway in figuring out which mutations are benign and which are deleterious. In so doing, they have increased the number of known CF-causing mutations from 22 to 127, accounting for 95 percent of the variations found in patients with CF.

In a summary of their research to be published online in Nature GeneticsAug. 25, the scientists say that characterizing those additional mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene will not only bring certainty to families about a CF diagnosis or carrier status, but will also accelerate the design process for new drugs tailored to a particular mutation. There already is one such individualized drug on the market.

"Since not all mutations cause disease, sequencing the DNA in both copies of your CFTR gene and finding an abnormality in one wouldn't tell us if you are a carrier for CF unless we knew if that abnormality causes CF," says Garry Cutting, M.D., professor of pediatrics in the McKusick-Nathans Institute of Genetic Medicine at the Johns Hopkins University School of Medicine. "Until this new work, more than a quarter of couples in which both partners were found to carry a CFTR mutation were left wondering if their mutations were going to affect their offspring. Now it's down to 9 percent," he says.