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HelpTest ID: SMCP Inherited Skeletal Muscle Channelopathy Gene Panel, Varies
Ordering Guidance
Targeted testing for familial variants (also called site-specific or known mutations testing) is available for the genes on this panel. See FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.
Customization of this panel and single gene analysis for any gene present on this panel are available. 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. For instructions for testing patients who have received a bone marrow transplant, call 800-533-1710.
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
Additional Information: To ensure minimum volume and concentration of DNA is met, the preferred volume of blood must be submitted. Testing may be canceled if DNA requirements are inadequate.
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. 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
Establishing a molecular diagnosis for patients with a skeletal muscle channelopathy
Identifying variants within genes known to be associated with a skeletal muscle channelopathy allowing for predictive testing of at-risk family members
Genetics Test Information
This test utilizes next-generation sequencing to detect single nucleotide and copy number variants in 5 genes associated with skeletal muscle channelopathies: ATP1A2, CACNA1S, CLCN1, KCNJ2, SCN4A. For more information see Method Description and Targeted Genes and Methodology Details for Inherited Skeletal Muscle Channelopathy Gene Panel.
Identification of a disease-causing variant may assist with diagnosis, prognosis, clinical management, recurrence risk assessment, familial screening, and genetic counseling for skeletal muscle channelopathies.
Method Name
Sequence Capture and Targeted Next-Generation Sequencing followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing
Reporting Name
Muscle Channelopathy Gene PanelSpecimen Type
VariesSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Clinical Information
Skeletal muscle channelopathies are neuromuscular disorders with onset predominantly in childhood and are characterized by episodic symptoms of either myotonia or paralysis. Skeletal muscle channelopathies can be divided into nondystrophic myopathies and periodic paralyses. The nondystrophic myotonias include myotonia congenita, paramyotonia congenita, and sodium channel myotonia and are characterized by muscle stiffness generated by voluntary movement. Other features include transient or prolonged weakness, pain associated with myotonia, and fatigue. The periodic paralyses include hyperkalemic periodic paralysis, hypokalemic periodic paralysis, and Andersen-Tawil syndrome and are characterized by episodic attacks of weakness, often triggered by diet or rest after exercise.
Reference Values
An interpretive report will be provided.
Interpretation
All detected variants are evaluated according to American College of Medical Genetics and Genomics recommendations.(1) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.
Clinical Reference
1. Richards S, Aziz N, Bale S, et al. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med. 2015;17(5):405-424. doi:10.1038/gim.2015.30
2. Vivekanandam V, Munot P, Hanna MG, Matthews E. Skeletal Muscle Channelopathies. Neurol Clin. 2020;38(3):481-491. doi:10.1016/j.ncl.2020.04.003
3. Matthews E, Holmes S, Fialho D. Skeletal muscle channelopathies: a guide to diagnosis and management. Pract Neurol. 2021;21(3):196-204. doi:10.1136/practneurol-2020-002576
Day(s) Performed
Varies
Report Available
14 to 21 daysTest 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
81403
81406 x 3
81479
81479 (if appropriate for government payers)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SMCP | Muscle Channelopathy Gene Panel | 102119-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 617728 | Test Description | 62364-5 |
| 617729 | Specimen | 31208-2 |
| 617730 | Source | 31208-2 |
| 617731 | Result Summary | 50397-9 |
| 617732 | Result | 82939-0 |
| 617733 | Interpretation | 69047-9 |
| 618192 | Additional Results | 82939-0 |
| 617734 | Resources | 99622-3 |
| 617735 | Additional Information | 48767-8 |
| 617736 | Method | 85069-3 |
| 617737 | Genes Analyzed | 48018-6 |
| 617738 | Disclaimer | 62364-5 |
| 617739 | Released By | 18771-6 |
Testing Algorithm
For more information see Neuromuscular Myopathy Testing Algorithm
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