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HelpTest Code DPYDQ Dihydropyrimidine Dehydrogenase Genotype, Varies
Ordering Guidance
This test does not detect or report variants other than the *2A, *7, *8, *10, *13, rs67376798, rs75017182, and rs115232898 alleles. Sequencing of the full gene is available for detection of additional variants as well as the alleles listed: order DPYDZ / Dihydropyrimidine Dehydrogenase, DPYD Full Gene Sequencing, Varies.
Specimen Required
Multiple genotype tests can be performed on a single specimen after a single extraction. See Multiple Genotype Test List for a list of tests that can be ordered together.
Submit only 1 of the following specimens:
Specimen Type: Whole blood
Container/Tube: Lavender top (EDTA)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
Specimen Stability Information: Ambient (preferred) 9 days/Refrigerated 30 days
Specimen Type: Saliva
Patient Preparation: Patient should not eat, drink, smoke, or chew gum 30 minutes prior to collection.
Supplies: Saliva Swab Collection Kit (T786)
Specimen Volume: 1 Swab
Collection Instructions: Collect and send specimen per kit instructions.
Specimen Stability Information: Ambient 30 days
Specimen Type: Extracted DNA
Container/Tube: 2-mL Screw top tube
Specimen Volume: 100 mcL (microliters)
Collection Instructions:
1. The preferred volume is 100 mcL at a concentration of 50 ng/mcL.
2. Provide concentration of DNA and volume on tube.
Specimen Stability Information: Frozen (preferred)/Ambient/Refrigerated
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing (Spanish) (T826)
2. If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.
Secondary ID
610052Useful For
Identifying individuals with genetic variants in DPYD who are at increased risk of toxicity when prescribed 5-fluorouracil (5-FU) or capecitabine chemotherapy treatment
Special Instructions
Method Name
Real-Time Polymerase Chain Reaction (PCR) with Allelic Discrimination Analysis
Reporting Name
DPYD Genotype, VSpecimen Type
VariesSpecimen Minimum Volume
Blood: 0.4 mL; Saliva, extracted DNA: see Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
5-Fluorouracil (5-FU) and its orally administered prodrug, capecitabine, are fluoropyrimidine-based chemotherapeutic agents that are widely used for the treatment of colorectal cancer and other solid tumors.
The dihydropyrimidine dehydrogenase (DPYD) gene encodes the rate-limiting enzyme for fluoropyrimidine catabolism and eliminates over 80% of administered 5-FU. Dihydropyrimidine dehydrogenase (DPYD) activity is subject to wide variability, mainly due to genetic variation. This results in a broad range of enzymatic deficiency from partial (3%-5% of population) to complete loss (0.2% of population) of enzyme activity.(2-5) Patients who are deficient in DPYD are at an increased risk for side effects and toxicity when undergoing 5-FU treatment.(6) In addition, pathogenic homozygous or compound heterozygous variants within DPYD are associated with dihydropyrimidine dehydrogenase (DPD) deficiency. DPD deficiency shows large phenotypic variability, ranging from no symptoms to a convulsive disorder with motor and intellectual disabilities.
The following table displays the DPYD variants detected by this assay, the corresponding star allele, and the effect on DPYD enzyme activity. Other or novel variations, besides those listed here, may also impact fluoropyrimidine-related side effects and tumor response.
Table. Enzyme Activity of Individual Star Alleles
|
DPYD allele |
cDNA nucleotide change |
Effect on enzyme activity |
|
*1 |
None (wild type) |
Normal activity |
|
*2A |
1905+1G>A |
No activity |
|
*7 |
299_302delTCAT |
No activity |
|
*8 |
703C>T |
No activity |
|
*10 |
2983G>T |
No activity |
|
*13 |
1679T>G |
No activity |
|
rs67376798 |
2846A>T |
Decreased activity |
|
rs75017182 |
1129-5923C>G |
Decreased activity |
|
rs115232898 |
557A>G |
Decreased activity |
Reference Values
DPYD Phenotype: Normal metabolizer
DPYD Activity Score: 2.00
DPYD Genotype: No variants were detected in the DPYD gene.
An interpretive report will be provided.
Interpretation
An interpretive report will be provided.
For additional information regarding pharmacogenomic genes and their associated drugs, see Pharmacogenomic Associations Tables. This resource also includes information regarding enzyme inhibitors and inducers, as well as potential alternate drug choices.
Method Description
Genomic DNA is extracted from whole blood or saliva. Genotyping for DPYD alleles is performed using a polymerase chain reaction (PCR)-based 5'-nuclease assay. Fluorescently labeled detection probes anneal to the target DNA. PCR is used to amplify the section of DNA that contains the variant. If the detection probe is an exact match to the target DNA, the 5'-nuclease polymerase degrades the probe, the reporter dye is released from the effects of the quencher dye, and a fluorescent signal is detected. Genotypes are assigned based on the allele-specific fluorescent signals that are detected.(Unpublished Mayo method)
Day(s) Performed
Monday through Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81232
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| DPYDQ | DPYD Genotype, V | 93199-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 610138 | DPYD Phenotype | 79719-1 |
| 610139 | DPYD Activity Score | 104665-5 |
| 613999 | DPYD Genotype | 45284-7 |
| 610140 | Interpretation | 69047-9 |
| 610141 | Additional Information | 48767-8 |
| 610142 | Method | 85069-3 |
| 610143 | Disclaimer | 62364-5 |
| 610144 | Reviewed by | 18771-6 |