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Congenital Myasthenic Syndrome via the SYT2 Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
SYT2 81479 81479,81479 $990
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8373SYT281479 81479,81479 $990 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Click here for costs to reflex to whole PGxome (if original test is on PGxome Sequencing platform).

Click here for costs to reflex to whole PGnome (if original test is on PGnome Sequencing platform).

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

Turnaround Time

3 weeks on average for standard orders or 2 weeks on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.


Genetic Counselors


  • Angela Gruber, PhD

Clinical Features and Genetics

Clinical Features

Congenital myasthenic syndromes (CMS) are disorders of the neuromuscular junction resulting from abnormalities of presynaptic, synaptic, or post synaptic proteins. CMS are characterized by fatigable weakness affecting limb, ocular, facial, and bulbar muscles. Neonates present with feeding problems, choking, feeble cry, and muscle weakness. Patients presenting in later childhood are seen with abnormal exercise-induced fatigue and difficulty running. Most patients present prior to 2 years of age, although rare exceptions have been reported (Croxen et al. 2002). Symptoms are extremely variable, and are in some case induced by febrile illness, infection, or excitement (Byring et al. 2002). Life threatening respiratory crises may occur in affected neonates or older children. CMS may be differentiated from myasthenia gravis, an acquired autoimmune disorder, by earlier age at onset and by negative serology tests, such as anti-acetylcholine receptor (AchR) and anti-Musk antibodies (Engel et al. 2015). CMS can be classified based on the location of the defect: presynaptic, synaptic, and postsynaptic. Congenital myasthenic syndrome-7 (CMS7) is potentially treatable complex presynaptic congenital myasthenic syndrome resulting from pathogenic variants in the SYT2 gene (Herrmann et al. 2014).


Congenital myasthenic syndrome-7 is caused by pathogenic variants in SYT2 and is inherited in autosomal dominant manner. The SYT2 gene encodes a synaptic vesicle membrane protein, which is an important calcium sensor and plays critical role in vesicular trafficking and exocytosis. The SYT2 gene contains nine exons (eight coding exons), encodes 419 amino acids and located at 1q32.1. Pathogenic variants in SYT2 disrupt synaptic vesicle exocytosis in a dominant-negative manner and interfere calcium-triggered neurotransmitter release in peripheral motor nerve terminals (Herrmann et al. 2014; Whittaker et al. 2015).

Clinical Sensitivity - Sequencing with CNV PGxome

Clinical sensitivity is not available because only a limited number of patients have been reported. The majority of reported pathogenic variants in SYT2 are missense, although one large duplication has been reported (Human Gene Mutation Database).

Testing Strategy

This test provides full coverage of all coding exons of the SYT2 gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing. PGnome panels typically provide slightly increased coverage over the PGxome equivalent. PGnome sequencing panels have the added benefit of additional analysis and reporting of deep intronic regions (where applicable).

Dependent on the sequencing backbone selected for this testing, discounted reflex testing to any other similar backbone-based test is available (i.e., PGxome panel to whole PGxome; PGnome panel to whole PGnome).

Indications for Test

A comprehensive diagnostic algorithm can be found in (Abicht and Lochmüller 2006).


Official Gene Symbol OMIM ID
SYT2 600104
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Myasthenic Syndrome, Congenital, 7, Presynaptic AD 616040


  • Abicht A., Lochmüller H. 2006. Congenital Myasthenic Syndromes. In: Pagon RA, Adam MP, Bird TD, Dolan CR, Fong C-T, and Stephens K, editors. GeneReviews™, Seattle (WA): University of Washington, Seattle. PubMed ID: 20301347
  • Byring R.F. et al. 2002. Neuromuscular Disorders. 12: 548-53. PubMed ID: 12117478
  • Croxen R. et al. 2002. Neurology. 59: 162-8. PubMed ID: 12141316
  • Engel A.G. et al. 2015. The Lancet. Neurology. 14: 420-34. PubMed ID: 25792100
  • Herrmann D.N. et al. 2014. American Journal of Human Genetics. 95: 332-9. PubMed ID: 25192047
  • Human Gene Mutation Database (Bio-base).
  • Whittaker R.G. et al. 2015. Neurology. 85: 1964-71. PubMed ID: 26519543


Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page

If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.

Specimen Types

Specimen Requirements and Shipping Details

PGxome (Exome) Sequencing Panel

PGnome (Genome) Sequencing Panel

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View Ordering Instructions

1) Select Test Method (Platform)

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2) Select Additional Test Options

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
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