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Lab Dept:
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Anatomic Pathology
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Test Name:
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TUBEROUS SCLEROSIS (TSC2) SEQUENCING
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General Information
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Lab Order Codes:
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TSC2
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Synonyms:
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TSC2 Mutation Evaluation
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CPT Codes:
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81407 – TSC2, full gene sequence (Molecular Pathology, Level 8)
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Test Includes:
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Detects a single sequence variation in TSC2 based on proband’s mutation.
The protein protein tuberin is encoded by 41 exons (2-42) from the TSC2 gene on chromosome 16p13.3. Testing is accomplished by amplifying each coding exon and ~50 bp of adjacent non-coding sequence, then determining the nucleotide sequence using standard dideoxy sequencing methods and a capillary electrophoresis instrument.
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Logistics
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Test Indications:
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Any combination of seizures, developmental delay, skin lesions, cortical tubers and hamartomas in various parts of the body. Individuals with a clinical presentation of tuberous sclerosis or having a family history of tuberous sclerosis. This test is specifically designed for heritable germline mutations and is not appropriate for detection of somatic mutations in tumor tissue.
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Lab Testing Sections:
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Anatomic Pathology - Sendouts
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Referred to:
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Prevention Genetics (Test: 1002)
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Phone Numbers:
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MIN Lab: 612-813-6280
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STP Lab: 651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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Maximum of 40 days, although many reported in 2-3 weeks
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Special Instructions:
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A test requisition must be sent with all specimens. Forms can be obtained through the following link: http://preventiongenetics.com/clinical-dna-testing/requisition-forms/
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Specimen
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Specimen Type:
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Whole blood
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Container:
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Lavender top (EDTA) tube
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Draw Volume:
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2-5 mL (Minimum: 1 mL for small babies) blood
Note: 5 mL preferred
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Processed Volume:
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Same as Draw Volume
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Collection:
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Routine venipuncture for blood specimens, invert gently to mix
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Special Processing:
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Lab Staff: Do Not centrifuge. Send whole blood in original collection container labeled with patient name, date of birth and medical record number and Prevention requisition filled out by provider. Ship specimens at room temperature in an insulated container.
During hot weather, include a frozen ice pack in the shipping container. Place a paper towel or other thin material between the ice pack and the blood tube.
In cold weather, include an unfrozen ice pack in the shipping container as insulation.
Send specimens Monday – Friday by overnight delivery. Specimens are accepted Monday – Saturday. Specimens collected Saturday and Sunday should be stored in the refrigerator and shipped on Monday or the next business day.
Note: Refrigerated specimens are stable for 1 week, room temperature specimens are stable for 48 hours.
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Patient Preparation:
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None
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Sample Rejection:
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Mislabeled or unlabeled specimens; frozen specimens
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Interpretive
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Reference Range:
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Interpretive report
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Critical Values:
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N/A
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Limitations:
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Any copy number changes smaller than 100bps (within the targeted region) may not be detected by our array.
This array may not detect deletion and amplification mutations present at low levels of mosaicism or those present in genes that have pseudogene copies or repeats elsewhere in the genome.
aCGH will not detect balanced translocations, inversions, or point mutations that may be responsible for the clinical phenotype.
Breakpoints, if happened outside the targeted gene, may be hard to define.
The sensitivity of this assay may be reduced when DNA is extracted outside of the laboratory.
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Methodology:
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Polymerase Chain Reaction (PCR) and bi-directional Sanger sequencing
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References:
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Prevention Genetics March 2013
Phone: 715-387-0484 Fax: 715-384-3661
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Updates:
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2/11/2013: CPT update
3/1/2013: Test moved from Athena to Prevention Genetics
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