Gene Symbol: CFTR
Chromosomal Locus: 7q31.2
Protein: cystic fibrosis transmembrane conductance regulator
Pseudonyms: CF, cystic fibrosis transmembrane conductance regulator, ATP-binding cassette sub-family C, member 7, Congenital Absence of the Vas Deferens (CAVD)
TURNAROUND TIME: 8 days
2012 AMA Code: 81220
TESTING METHODOLOGY: This assay uses PCR and cleavase enzymes to recognize and cleave specific mutations in CFTR gene. This test examines a panel of 46 most common mutations in the US and European populations. The mutations in the ACOG/ACMG panel are included.
- Collect: Prefer two 5ml whole blood EDTA (lavender top) tube.
- Min. Collection: 0.7 ml whole blood EDTA.
- Transport: blood EDTA at Room Temp shipped regular next day air (No Saturday delivery; store specimen at 4°C and ship Monday).
- Stability: Ambient: up to 7 days; Refrigerated: 2 weeks. Frozen: unacceptable
- Unacceptable Conditions: Serum. Frozen or severely hemolyzed blood. Clotted blood.
- Prenatal testing: Direct: 5ml direct unspun amniotic fluid or 15mg CVS tissue with a backup flask growing. Culture: confluent T25 flask. Maternal blood sample is required for maternal cell contamination studies.
Counseling and informed consent are recommended for genetic testing. A consent form
is available as a resource but not required.
Incidence: 1 in 3,500 in the US and Northern European Caucasian populations are affected with Cystic Fibrosis. 1 in 20 of this same population are carriers of a Cystic Fibrosis mutation. Significant differences occur in other ethnic populations.
Inheritance: Autosomal recessive. However, a single mutation may lead to Congenital Absence of the Vas Deferens (CAVD) in some cases.
Disease Characteristics: Classical cystic fibrosis affects salt regulation in epithelia which affects secretory organs. Pulmonary disease resulting in lower airway inflammation and chronic endobronchial infection, progressing to end-stage lung disease is the most dramatic symptom. However, meconium ileums can occur at birth and pancreatic insufficiency leads to food malabsorption. Also more than 95% of males with CF are infertile. A milder form of CF, CAVD results in azoospermia and infertility but none of the more severe symptoms.
Molecular Genetic Mechanism: More than 1000 point mutations and small deletions are known to occur throughout the gene.
Clinical Sensitivity: The panel identifies >90% of the mutations in the US and Northern European Caucasian populations. Significant differences in detection rates occur in other ethnic populations.
Analytical Sensitivity: 99%
Test Limitations: This test only detects the 46 mutations that are in the panel. Rare diagnostic errors can occur due to primer / probe site mutations or rare polymorphisms.
INDICATIONS FOR USE:
- Preconception screening of Caucasian couples as recommended by ACOG and ACMG.
- Couples with a family history of CF that wish to undergo prenatal testing.
- Newborns with failure to thrive or other suggestive clinical symptoms.