Cystic Fibrosis: CFTR Sequencing

Turnaround Time

28 days

CPT Code(s)

81223

Cost

$1,500

Genes

• Cystic Fibrosis

Cystic fibrosis is a common autosomal recessive disorder that affects many functions of the body such as respiration, endocrine function, and reproduction. Although great strides in treatment have increased the length and quality of life for CF patients, it is nearly always fatal by the fourth decade of life. Sweat chloride testing remains the gold standard for diagnosis of CF, however DNA analysis is indicated not only for CF patients but also for their extended families. In addition to providing information about the specific mutations that cause CF, molecular testing allows rapid detection of cystic fibrosis carriers and can determine if the patient has a pancreatic sufficient or insufficient type of the disease. This information plays a large role in clinical management of the affected individual. Over 2000 variants have been reported in the CFTR gene. The carrier rates of the disorder are 1/25 Caucasians, 1/60 African-Americans, 1/46 Hispanics, 1/90 Asians, and 1/29 in the Ashkenazi Jewish population.

Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.

Sanger Sequencing

Over 98% of patients with cystic fibrosis have at least one causative sequence variant in CFTR.

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA, dried blood spots, and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Prenatal diagnosis is available if the familial mutations are known or there are clinical features identified via ultrasound suggestive of a diagnosis in the fetus. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.