Reference Interval:
By report
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| Interpretive Data: |
Background Information for Cytochrome P450 2D6 (CYP2D6) 17 Mutations:
Characteristics: Some CYP2D6 mutations cause impaired drug metabolism, a major cause of adverse drug reactions or lack of drug response. Drugs metabolized by CYP2D6 include antiestrogens (tamoxifen), alpha-blockers, analgesics, anticonvulsives, antidepressants, antidiabetics, antihypertensives, antipsychotics, antitussives, beta blockers, cardioactives, norepinephrine reuptake inhibitors, and stimulants. Additionally, many drugs inhibit CYP2D6 activity, and may affect drug response.
Inheritance: Autosomal recessive.
Cause: CYP2D6 gene mutations.
Mutations Detected: All common and most rare alleles with known clinical significance.
Negative: No mutations detected is predictive of *1 alleles.
Functional: *2A (-1584C>G), *2 or *35 (-1584C>G + additional mutations defining haplotype assignment 1661G>C/2850C>T/4180G>C).
Decreased function: *9 (2613-5delAGA), *10 (100C>T), *17 (1023C>T), *41 (2988G>A).
Non-functional: *3 (2549A>del), *4 (1846G>A), *5 (gene deletion),*6 (1707T>del), *7 (2935A>C), *8 (1758G>T), *11 (883G>C), *12 (124G>A), *14 (1758G>A), *15 (138 insT).
Increased function: Duplicated functional alleles.
Incidence of Poor Metabolizer Phenotype: 10 percent of Caucasians and Hispanics, 2 percent of African Americans, and 1 percent of Asians.
Penetrance: Unknown; drug dependent.
Clinical Sensitivity: Greater than 95 percent of deleterious CYP2D6 mutations are detected in Caucasians; sensitivity is unknown in other ethnicities.
Methodology: PCR and allele-specific primer extension (ASPE) by bead array with fluorescence detection.
Analytical sensitivity and specificity: Greater than 99 percent.
Limitations: Only the targeted CYP2D6 mutations will be detected. Mutations in other genes will not be detected. Rare diagnostic errors can occur due to primer site mutations. Mutation detection is not a substitute for therapeutic drug monitoring. Non-genetic factors may also affect drug metabolism.
Please refer to Statement C in the Compliance Statements section in the front of the Laboratory Test Directory.
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| CPT Code(s): |
83890 Isolation; 83892 x2 Enzymatic digestion; 83900 Amplification multiplex; 83901 Amplification; 83914 x17 Mutation identification; 83909 Separation and identification; 83912 Interpretation and report - Additional CPT code modifiers may be required for procedures performed to test for oncologic or inherited disorders.
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