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Comprehensive Epilepsy (NGS Panel and Copy Number Analysis + mtDNA)

CPT: 81419, 81460, 81465

Genes Assessed


      Specimen Requirements


      Specimen

      Blood | Extracted DNA | Cultured Fibroblasts | Muscle | Buccal Cells


      Volume

      Blood: Draw blood in a lavender top EDTA tube, Sample Stability: 5-7 days, Preferred volume: 4 ml, Minimum volume: 2 ml, DO NOT FREEZE. Extracted DNA: From leukocytes, muscle, or fibroblasts: Preferred quantity: 1 microgram, Minimum quantity: 800 nanograms. Genomic DNA should be eluted in sterile Dnase/Rnase free water or TE. The A260:A280 ratio should be 1.8-2.0. Cultured Fibroblasts: Two T-25 flasks of fibroblasts, preferably ~90% confluent. TAT will be extended by 7-14 days if cells are not confluent upon arrival. Muscle: 50-75 milligrams muscle snap frozen in liquid nitrogen and maintained at -80°Celsius or below. Buccal Cells: One buccal swab should be used for collection. Do not discard solution in collection tube. Follow collection instructions supplied. Stability at ambient temperature is 60 days.


      Container

      Blood: Lavender-Top (EDTA) Tube, Buccal Swab from MNG Kit, Tissue or Extracted DNA: Sterile screw capped vial, Cultured cells: T25 flask


      Collection

      Blood: Specimens should be shipped overnight in a secure container at room temperature. Extracted DNA: Should be shipped overnight at room temperature. If previously frozen, DNA can be shipped in an insulated container with wet or dry ice. Cultured Fibroblasts: T-25 flasks containing fibroblasts should be shipped in an insulated container at room temperature. Flasks should be completely filled with media and cells should be ~90% confluent. Fibroblast samples must be certified free from Mycoplasma. MNG is able to perform this service for a small charge (TC05). For NGS panels, TAT will be extended by 7-14 days if cells are not confluent upon arrival. Muscle: Samples should be shipped frozen in an insulated container with 5-7 lbs. dry ice, overnight. Buccal cells: Should be shipped overnight in a secure container at room temperature.


      Storage Instructions

      Blood - ship ASAP, but stable up to 5 days post-collection at room temperature. DO NOT FREEZE; Swab - 60 day post-collection room temperature stability; DNA - ship at room temperature after extraction; Fibroblasts - ship flask in insulated container at room temp or refigerated; Muscle - ship in insulated container with 5-7 lbs of dry ice


      Stability Requirements

      Room Temperature: Blood - 5 days, Swab - 60 days, DNA - 30 days, Muscle - 0 days, Fibroblasts - 2-3 days; Refrigerated: Blood - 5 days, Swab - 60 days, DNA - 30 days, Muscle - 0 days, Fibroblasts - 2-3 days; Frozen: Blood - DO NOT FREEZE, Swab - 60 days, DNA - Indefinitely, Muscle - Indefinitely, Fibroblasts - Indefinitely; Freeze/Thaw: None


      Causes for Rejection

      Extracted DNA A260:A280 ratio of outside of 1.8-2.0 range; Frozen blood EDTA tube; Thawed and/or fatty muscle sample; Insufficient buccal cell collection


      Test Details


      Use

      Epilepsy is a chronic seizure disorder characterized by seizures that usually recur unpredictably in the absence of a consistent provoking factor. Most epilepsy syndromes are genetically heterogeneous; pathogenic variants in different genes cause the same syndrome in different individuals or families, and only a fraction of the potential genetic causes have so far been identified. Genetic assessment is enhanced when clinical information is available. Although a positive test result can confirm or suggest that an individual has a specific syndrome, a negative test result might be uninformative. For instance, fewer than one in five individuals with autosomal dominant nocturnal frontal lobe epilepsy have a pathogenic variant in any of the genes currently associated with that disorder. Conversely, in syndromes with incomplete penetrance and variable expressivity, a positive test result in an unaffected family member does not necessarily mean that the individual will develop epilepsy in the future, nor can it predict the specific phenotype if the individual does. An important example of this problem is genetic epilepsy with febrile seizures plus (GEFS+), in which some family members with a SCN1A variant remain unaffected, and phenotypes in affected family members vary from simple age-limited febrile seizures to severe epileptic encephalopathies (PMID:24733164).


      Methodology

      Next-Generation Sequencing


      Recommended MNG Kits

      SINGLE Blood Genetic Testing, Buccal Swab Genetic Testing


      Z-Code

      ZB5P1