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Test ID: CMSP Inherited Congenital Myasthenic Syndrome 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 for instructions for testing patients who have received a bone marrow transplant.

Specimen Type: Whole blood

Container/Tube: 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 congenital myasthenic syndrome

 

Identifying variants within genes known to be associated with congenital myasthenic syndrome, 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 28 genes associated with congenital myasthenic syndromes: AGRN, ALG14, ALG2, CHAT, CHRNA1, CHRNB1, CHRND, CHRNE, COL13A1, COLQ, DNM2, DOK7, DPAGT1, GAA, GFPT1, GMPPB, LAMB2, LRP4, MUSK, PLEC, PREPL, RAPSN, SCN4A, SLC18A3, SLC25A1, SLC5A7, SYT2, VAMP1. For more information see Targeted Genes and Methodology Details for Inherited Congenital Myasthenic Syndrome Gene Panel and Method Description.

 

Identification of a disease-causing variant may assist with diagnosis, prognosis, clinical management, recurrence risk assessment, familial screening, and genetic counseling for congenital myasthenic syndromes.

Method Name

Sequence Capture and Targeted Next-Generation Sequencing followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing

Reporting Name

Congenital Myasthenia Gene Panel

Specimen Type

Varies

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Varies

Clinical Information

Congenital myasthenic syndromes occur as a result of compromised neuromuscular transmission. Clinical manifestations include fatigable weakness involving ocular, bulbar, and limb muscles. The severity and disease course are highly variable, but individuals usually present in infancy or early childhood. The clinical phenotype associated with a neonatal onset can include feeding difficulties, poor suck and cry, choking spells, eyelid ptosis, and muscle weakness. The clinical phenotype associated with a later childhood onset can include abnormal muscle fatigue, delayed motor milestones, ptosis, and extraocular muscle weakness.

 

The combination of the wide variability in symptoms and age of presentation can make congenital myasthenic syndromes hard to diagnosis. Given that congenital myasthenic syndromes are a heterogeneous group of disorders, multigene panels can be an efficient and cost-effective way to establish a molecular diagnosis for individuals. Having a molecular diagnosis can have therapeutic implications.

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

2. Lyadurai SJP. Congenital myasthenic syndromes. Neurol Clin. 2020;38(3):541-552

Day(s) Performed

Varies

Report Available

21 to 35 days

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

81443

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CMSP Congenital Myasthenia Gene Panel 103732-4

 

Result ID Test Result Name Result LOINC Value
617520 Test Description 62364-5
617521 Specimen 31208-2
617522 Source 31208-2
617523 Result Summary 50397-9
617524 Result 82939-0
617525 Interpretation 69047-9
618176 Additional Results 82939-0
617526 Resources 99622-3
617527 Additional Information 48767-8
617528 Method 85069-3
617529 Genes Analyzed 48018-6
617530 Disclaimer 62364-5
617531 Released By 18771-6

Testing Algorithm

For more information see Neuromuscular Myopathy Testing Algorithm

Mayo Clinic Laboratories | Genetics and Genomics Additional Information:

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