#ExistRefRange>Negative: This specimen is negative for 3199de16 and confirmed positive for I148T. Consequently, the patient's I148T cystic fibrosis mutation may represent a variant of mild clinical significance. This test is specific to the 3199del6 and I148T mutations; other mutations are not ruled out.
#ExistInterpData>Background Information for Cystic Fibrosis (CFTR) 3199Del6 Mutation:
Characteristics: The 3199del6 mutation is offered to individuals who have a documented I148T mutation from a previous CF mutation panel. Recent evidence indicates I148T may be a benign polymorphism unless it is located on the same chromosome (in cis) with 3199del6. I148T is represented in approximately 6 percent of CF carriers but only 0.06 percent of those affected with CF. Those with I148T who are affected with CF also have 3199del6 in cis.
Incidence of Classic CF: 1 in 3,000 Caucasians or Ashkenazi Jewish, 1 in 8,000 Hispanics, 1 in 15,000 African American, 1 in 32,000 Asians.
Carrier frequency: 1 in 25 in European Caucasians and Ashkenazi Jews, 1 in 46 Hispanics, 1 in 65 African Americans, 1 in 90 Asian Americans
Inheritance: Autosomal recessive
Penetrance: Homozygotes for 3199del6 have not been reported; therefore, the clinical severity of this mutation is unknown. However, compound heterozygotes for I148T/3199del6 and the common F508del mutation have symptoms of classical CF.
Cause: CF is caused by two CFTR mutations on opposite chromosomes
Methodology: Polymerase chain reaction (PCR) and fluorescent hybridization probes.
Analytical Sensitivity & Specificity: 99 percent
Limitations: This test is specific for the cystic fibrosis (CF) 3199del6 mutation. Other mutations in the CFTR gene will not be detected.
This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.
See Compliance Statement C: www.aruplab.com/CS