SCN1A Sequencing, Full Gene

CPT: 81407
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Test Details

Synonyms

  • Dravet Syndrome, FEB3

Test Includes

This test covers all coding nucleotides of gene SCN1A, plus at least two and typically 20 flanking intronic nucleotides upstream and downstream of each coding exon, covering the conserved donor and acceptor splice sites, as well as typically 20 flanking nucleotides in the 5' and 3' UTR.

Use

Confirms a diagnosis of a SCN1A-related seizure disorder, including but not limited to severe myoclonic epilepsy of infancy (SMEI, also known as Dravet Syndrome), intractable childhood epilepsy with generalized tonic-clonic seizures (ICE-GTC), generalize epilepsy with febrile seizures plus (GEFS+).

Limitations

This method does not reliably detect mosaic variants; large deletions; large duplications, inversions, or other rearrangements; deep intronic variants or variants outside of the regions targeted by this analysis. It may be affected by allele-dropout, it may not allow determination of the exact numbers of T/A or microsatellite repeats, and it does not allow any conclusion as to whether two heterozygous variants are present on the same or on different chromosome copies.

Results of this test are for investigational purposes only. The performance characteristics of this assay have been determined by LabCorp. The result should not be used as a diagnostic procedure without confirmation of the diagnosis by another medically established diagnostic product or procedure.

Methodology

DNA sequencing

Additional Information

SCN1A-related seizure disorders encompass a spectrum of autosomal dominant disorders that ranges from simple febrile seizures (FS) and generalized epilepsy with febrile seizures plus (GEFS+) at the mild end to Dravet syndrome and intractable childhood epilepsy with generalized tonic-clonic seizures (ICE-GTC) at the severe end. Less commonly observed phenotypes include myoclonic-astatic epilepsy (MAE or Doose syndrome), Lennox-Gastaut syndrome (LGS), infantile spasms, and vaccine-related encephalopathy and seizures. Individuals with seizures on the more severe end of the spectrum often carry a de novo pathogenic variant while individuals on the milder end of the spectrum often have an inherited pathogenic variant. In addition, the clinical presentation of family members carrying the same pathogenic SCN1A variant can vary. Consequently, testing combined with a detailed clinical history is recommended for the parents of any child with a SCN1A pathogenic variant or variant of uncertain significance.

Specimen Requirements

Specimen

Whole blood

Volume

7 mL

Minimum Volume

3 mL

Container

Lavender-top (EDTA) tube or yellow-top (ACD) tube

Storage Instructions

Maintain at room temperature or refrigerate at 4°C.

Causes for Rejection

Frozen or hemolyzed specimen; quantity not sufficient for analysis; improper container

Clinical Information

References

Claes L, Ceulemans B, Audenaert D, et al. De Novo SCN1A mutations are a major cause of severe myoclonic epilepsy of infancy, Hum Mutat. 2003 Jun; 21(6):615-621. 12754708
Mulley JC, Scheffer IE, Petrou S, Dibbens LM, Berkovic SF, Harkin LA. SCN1A mutations and epilepsy. Hum Mutat. 2005 Jun; 25(6):535-542. 15880351
National Institute of Neurological Disorder and Seizures. Seizures and Epilepsy: Hope Through Research. National Institutes of Health Publications N° 04-156, originally published May 2004; updated March 2, 2006. Available at: http://www.ninds.nih.gov/disorders/epilepsy/detail_epilepsy.htm

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
511236 SCN1A DNA Sequencing 41765-9 511237 SCN1A DNA Sequencing 41765-9

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