Cystic Fibrosis- Mutation Screening Panel 

• Cystic fibrosis (CF) currently affects approximately 30,000 children and adults in the United States
• CF, one of the most common fatal inherited diseases, is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene
• A child must inherit two such genes, one from each parent, to develop the disease

• Affected individuals have abnormal transport of chloride within cells lining the lungs and pancreas to the outer surface of those organs, resulting in the production of an abnormally thick mucus
• Of a variety of symptoms associated with CF, the most common include very salty-tasting skin, persistent coughing, wheezing or pneumonia, bulky stools and poor weight gain despite excessive appetite
• The treatment of CF is determined by the stage of the disease and the organs involved, but include chest physical therapy to dislodge the thick mucus from the lungs, antibiotic treatment for lung infections and special diets and supplements to increase nutrient absorption
• The current life expectancy for individuals affected with CF is approximately 30 years

• The ACMG/ACOG published recommendations to offer CF carrier screening to non-Jewish Caucasians and Ashkenazi Jews, and to make screening available to other ethnic and racial group
• “ACOG now recommends the OB/GYNs make DNA screening for cystic fibrosis available to all couples seeking preconception or prenatal care- not just those with a personal or family history of carrying the gene, as previously recommended.”

• Mutations in the CFTR gene may result is defective processing of its protein and alter the function and regulation of this channel
• More than 1,000 mutations have been identified within the CFTR gene
• The D508 mutation is the most common gene variant, accounting for approximately 66% of all CF mutant alleles worldwide
• The remaining CFTR mutations vary greatly in their frequency and distribution; however, the majority of these mutations are either private or limited to a small number of individuals
• The American College of Medical Genetic (ACMG) and the American College of Obstetrics and Gynecologists (ACOG) recommend a core mutation panel of 23 mutations for pan-ethnic screening in the U.S. population (see table below)

• A thorough assessment of the ethnic background of every individual referred for testing is unlikely due to the genetic heterogeneity within the U.S. population and the intermixture among ethnic groups