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HelpTest ID CSTB CSTB Gene, Repeat Expansion Analysis, Varies
Ordering Guidance
This test only detects dodecamer repeat expansions. If testing for both dodecamer repeat expansions and other CSTB variants is requested, order a custom gene panel for the CSTB gene. For more information see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies.
Shipping Instructions
Specimen preferred to arrive within 96 hours of collection.
Specimen Required
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Specimen Type: Whole blood
Container/Tube:
Preferred: Lavender top (EDTA) or yellow top (ACD)
Acceptable: Any anticoagulant
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)/Refrigerated
Forms
1. New York Clients-Informed consent is required. Please 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. Molecular Genetics: Neurology Patient Information
3. If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.
Useful For
Molecular confirmation of clinically suspected CSTB-related progressive myoclonic epilepsy
Identifying full penetrance dodecamer repeat expansions within CSTB known to cause CSTB-related progressive myoclonic epilepsy, allowing for predictive testing of at-risk family members
Impacting patient treatment and management through the identification of a specific underlying etiology for epilepsy (eg, directing appropriate use of anti-epileptic drugs and other treatment modalities)
Genetics Test Information
This test assesses for CCC-CGC-CCC-GCG dodecamer repeat expansions in the promoter region of CSTB to confirm a molecular diagnosis of CSTB-related progressive myoclonic epilepsy, also known as progressive myoclonic epilepsy type 1 (EPM1).
Special Instructions
Method Name
Polymerase Chain Reaction (PCR)
Reporting Name
CSTB, Repeat Expansion AnalysisSpecimen Type
VariesSpecimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | ||
| Frozen | |||
| Refrigerated | |||
Reference Values
Normal: <5 dodecamer repeats
Repeat Size of Uncertain Significance: 5-29 dodecamer repeats
Full Penetrance Expansion: >29 dodecamer repeats
An interpretive report will be provided.
Day(s) Performed
Varies
Report Available
28 to 42 daysPerforming 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
81188
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CSTB | CSTB, Repeat Expansion Analysis | 41110-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 616516 | Result Summary | 50397-9 |
| 616517 | Result | 82939-0 |
| 616518 | Interpretation | 69047-9 |
| 616519 | Reason for Referral | 42349-1 |
| 616520 | Specimen | 31208-2 |
| 616521 | Method | 85069-3 |
| 616522 | Source | 31208-2 |
| 616523 | Released By | 18771-6 |
NY State Approved
YesTesting Algorithm
For more information see Epilepsy: Unexplained Refractory and/or Familial Testing Algorithm