The Food and Drug Administration (FDA) has approved the first DNA-based blood test to help detect cystic fibrosis. The Tag-It Cystic Fibrosis Kit directly analyzes human DNA to find genetic variations indicative of the disease. The test will be used to help diagnose cystic fibrosis in children and to identify adults who are "carriers" of the gene variations.
"This test represents a significant advance in the application of genetic technology and paves the way for similar genetic diagnostic tests to be developed in the future," said Daniel Schultz, MD, director of FDA’s Center for Devices and Radiological Health.
Cystic fibrosis is a serious genetic disorder affecting the lungs and other organs that often leads to an early death. It is the number one cause of chronic lung disease in children and young adults, as well as the most common fatal hereditary disorder affecting Caucasians in the United States. The disease affects about one in 2500-3300 Caucasian babies. Half of the people with cystic fibrosis die by the age of 30.
The Tag-It test identifies a group of variations in a gene called the "cystic fibrosis transmembrane conductance regulator" or CFTR gene that causes cystic fibrosis. FDA approved Tag-It based on a manufacturer study of hundreds of DNA samples showing that the test identifies the CFTR gene variations with a high degree of certainty. The manufacturer also provided FDA with a broad range of supporting peer-reviewed literature.
Since Tag-It detects a limited number of the more than 1300 genetic variations identified in the CFTR gene, the test should not be used alone to diagnose cystic fibrosis. Physicians should interpret test results in the context of the patient’s clinical condition, ethnicity, and family history. Also, patients may need genetic counseling to help them understand their test results.
The Tag-It Cystic Fibrosis Kit is manufactured by Tm Bioscience Corporation of Toronto, Canada.