|
|
Lab Dept:
|
Anatomic Pathology
|
Test Name:
|
COLARIS AP®(MYH) KNOWN MUTATION
|
General Information
|
Lab Order Codes:
|
SSCAM
|
Synonyms:
|
Single Site Colaris AP for MYH; MYH-associated polyposis, known mutation
|
CPT Codes:
|
83891 - Isolation or extraction of highly purified nucleic acid
83898 - Amplification of patient nucleic acid, single primer pair, each pair
83904 - Mutation identification by sequencing, single segment, each segment
83894 - Separation by gel electrophoresis
|
Test Includes:
|
Mutation specific analysis for MYH.
|
Logistics
|
Test Indications:
|
Gene mutations in the MYH genes (leading to MAO) are passed on in families in an autosomal recessive pattern. This means that, in order for an individual to be affected with MAP, he or she would have inherited mutations in both copies of the MYH genes, one from each parent. Parents of this individual are considered “carriers” of a single MYH gene mutation but are usually not affected with colorectal polyps or cancer. In most cases, children of affected individuals will be “carriers” of a single MYH gene mutation as well. Siblings of the patient are at 25% risk to carry the same two mutations in their MYH genes. Due to the autosomal recessive pattern of inheritance, individuals affected with MAP will often have no family history of colorectal polyps or cancer.
|
Lab Testing Sections:
|
Anatomic Pathology - Send-Outs
|
Referred to:
|
Myriad Genetic Laboratories, Inc.
|
Phone Numbers:
Minneapolis:
Saint Paul:
|
|
612-813-6280
|
651-220-6555
|
Test Availability:
|
Sunday - Thursday
|
Turnaround Time:
|
3 to 4 weeks
|
Special Instructions:
|
Obtain special kit from Myriad Genetic Laboratories and complete request and consent forms provided in the kit prior to sending the patient or specimen to the laboratory.
Must specify variant(s), and relationship of known mutation carrier to patient (e.g. sister). An Informed consent signed by an individual legally authorized to do so (e.g. The Health Care Provider) is required. (Note: Test requests without a signature will not be processed). Ancestry and patient history are requested.
|
Specimen
|
Specimen Type:
|
Whole blood
|
Container:
|
Lavender top (EDTA) tube
(2-10 mL EDTA tubes are provided in the Myriad kit)
|
Draw Volume:
|
20 mL blood
|
Processed Volume:
|
Same as Draw Volume
|
Collection:
|
Routine venipuncture
Collect 20 mL of whole blood into 2-10 mL lavender top ( EDTA) tubes provided in Myriad Kit. Invert specimens gently to mix. Label tubes appropriately. Send collected specimens and collection kit to the laboratory as soon as possible. Specimens are viable for 72 hours. Avoid collections on Friday, if possible. It is recommended that specimens not be shipped on Friday. Contact the laboratory prior to collections on Friday or Saturday.
|
Special Processing:
|
Lab Staff: Do not centrifuge specimens. Specimens should remain in original collection containers. Ship at ambient temperature Monday through Thursday. Specimens must be received by reference lab within 72 hours of collection.
Specify relationship of known mutation carrier to patient. Specify Mutations. Ship specimen in kit and mailer provided by Myriad.
Specimens should be kept at room temperature and shipped according to the test kit instructions.
|
Patient Preparation:
|
If patient is receiving chemotherapy, collected specimen before administration of chemo.
|
Sample Rejection:
|
Wrong tube type, insufficient DNA extracted, specimen too old, mislabeled or unlabeled specimens
|
Interpretive
|
Reference Range:
|
The test will be reported with one of the following:
Positive for specified mutation(s): The specific mutation(s) designated has been found. This may be a mutation(s) that was previously identified in another family member. Such a result indicates an increased risk for cancer.
Negative for specified mutation: The specific mutation(s) designated is absent. This usually means that the risk of cancer is no greater than that of the general population. In rare cases, more than one inherited mutation runs in a family and a negative result from a single site, or mutation-specific, analysis would rule out only the specified mutation(s).
|
Critical Values:
|
N/A
|
Limitations:
|
Analysis of MYH includes analysis for Y165C and G382D, and does not rule out the possibility of other mutations. Unequal allele amplification may result from rare polymorphisms under primer sites.
Additional information about performance characteristics of the MYH analysis is available in the MYH Technical Specifications.
|
Methodology:
|
DNA analysis, by direct sequence or Southern blot methods, for a specified mutation in APC. Southern blot analysis of all exons of APC is performed for all requests for single site mutation analysis of a large rearrangement.
Blood samples are assigned a unique bar-code for robotic specimen tracking. DNA is extracted and purified from white cells isolated from each sample.
Sequence Analysis: Aliquots of patient DNA are each subjected to polymerase chain reaction (PCR) amplification reactions. The amplified products are each directly sequenced in forward and reverse directions using fluorescent dye-labeled sequencing primers. Chromatographic tracings of each amplicon are analyzed by a proprietary computer-base review followed by visual inspection and confirmation. Genetic variants are detected by comparison with a consensus wild-type sequence constructed for each gene. All potential genetic variants are independently confirmed by repeated PCR amplification of the indicated gene region(s) and sequence determination as above.
Southern blot analysis: Aliquots of genomic DNA are digested individually with three restriction enzymes or combinations of enzymes for APC analysis. Digested DNA is electrophoresed in an agarose gel, transferred to a membrane, and hybridized with a gene-specific probe labeled with 32P. The probe binds to all fragments containing coding; sequences of that gene Autoradiographs and phosphorimages are produced and analyzed for the presence of novel bands and for fragment dosage, from which it is determined which, if any, exons have been deleted or duplicated, Positive and negative controls are run with deleted or duplicated. Positive and negative controls are run with each batch. All potential mutations are independently confirmed.
|
Contraindications:
|
No family history
|
References:
|
Colaris AP Technical Specifications, Myraid Genetic Laboratories, Inc. 29 Aug 2005
|
Myriad Genetic Laboratories June 2006
(801) 584-3600 Fax (801) 584-3640
|
