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|Type||Specimen Requirements||Specimen Collection and Shipping|
|Whole Blood||In EDTA (purple top) or ACD (yellow top) tube:|
Infants (<2 years): 2-3 ml
Children (>2 years): 3-5 ml
Older Children & Adults: 5-10 ml
|Refrigerate until time of shipment. Ship sample within 5 days of collection at room temperature with overnight delivery.|
|Saliva||OrageneTM Saliva Collection kit (available through EGL) used according to manufacturer instructions.||Store sample at room temperature. Ship sample within 5 days of collection at room temperature with overnight delivery.|
Cystic fibrosis (CF) is a chronic genetic condition involving multiple organ systems . Classical CF primarily involves the respiratory and digestive systems, and may have a range of clinical severity. Pulmonary symptoms often include lower airway inflammation, chronic cough, chronic sinusitis, and recurrent infections. Digestive symptoms often include meconium ileus, pancreatic insufficiency resulting in malabsorption and/or failure to thrive, diabetes mellitus, and hepatobiliary disease. Congenital bilateral absence of the vas deferens (CBAVD) is seen in men without pulmonary or digestive symptoms of CF, and results in azoospermia . CBAVD is a significant cause of male infertility.
CF is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Individuals with mutations in the CFTR gene may also present with milder or atypical symptoms such as pancreatitis or chronic sinusitis.
The incidence of CF is approximately 1 in 3200 live births among Caucasians and is inherited in an autosomal recessive pattern. The carrier frequency is estimated to be approximately 1 in 22-28 in the Caucasian population, 1 in 29 in the Ashkenazi Jewish population, 1 in 60-65 in the African American population, 1 in 46 in the Hispanic population and 1 in 90 in the Asian population.
Initial evaluation and screening of patients for CFTR mutations is accomplished through a panel of 23 common mutations as recommended by the American College of Medical Genetics Subcommittee on Cystic Fibrosis  and the American College of Obstetrics and Gynecologists . The detection rate of this panel depends on the patient's ethnicity.
When the common mutation panel is negative and mutations to the CFTR gene are suspected, sequencing of the entire gene is recommended to detect rare mutations. For patients with mutations not identified by full gene sequencing, a separate deletion/duplication assay is available using a targeted CGH array (JL).
Click here for the GeneReviews summary on this condition.
1. Moskowitz et al. CFTR-related disorders (2005). www.genetests.org
2. Xu et al. Cystic fibrosis transmembrane conductance regulator is vital to sperm fertilizing capacity and male fertility (2007). PNAS 104(23):9816-21.
3. Watson, M. et al. Cystic Fibrosis population carrier screening: 2004 revision of the American College of Medical Genetics mutation panel (2004). Genet Med 6(5):387-91.
4. ACOG Committee Opinion. Update on Carrier Screening for Cystic Fibrosis (2005). Obstetr Gynecol 106:1465-8.
5. Strom et al. (2003) Extensive sequencing of the cystic fibrosis transmembrane regulator gene: assay validation and unexpected benefits of developing a comprehensive test. Genet Med 5(1):9-14.
6. Chevalier-Porst (2005) Identification and Characterization of Three Large Deletions and a Deletion/Polymorphism in the CFTR Gene. Hum Mut Mutation in Brief #806 Online
Completion of the cystic fibrosis common mutation panel should be completed PRIOR to CFTR gene sequence analysis.
Submit copies of diagnostic biochemical test results (i.e. sweat test results) with the sample, if appropriate. Contact the laboratory if further information is needed.
Sequence analysis is required before deletion/duplication analysis by targeted CGH array. If sequencing is performed outside of Emory Genetics Laboratory, please submit a copy of the sequencing report with the test requisition.