• Test Code:
    2590
  • Department:
    Molecular Genetics
  • Test Synonyms:
    SODCOL4A1EMX2HESX1OTX2SHHSIX3SOX2
  • CPT Code(s):
    81408
Background:

Disorders causing brain malformations are phenotypically heterogeneous; mutations in certain genes have been associated inherited conditions causing brain developmental issues. Septo-optic dysplasia (SOD) specifically causes brain malformations early in development. Major clinical phenotypes include abnormalities of the optic nerve, midline brain deformities, and pituitary hypoplasia. Schizencephaly may also be a feature in septo-optic dysplasia; genes associated with schizencephaly have been added to this panel. Septo-optic dysplasia and schizencephaly have been shown to be autosomal dominant and recessive.

Reasons for Referral:

  • Suspected genetic etiology of a brain malformation
  • Carrier testing
  • Positive family history

Methodology:

Next generation sequencing will analyze the exons or coding regions of 7 genes associated with Septo-optic dysplasia and Schizencephaly using Illumina NextSeq 500/550 technology and preparing samples using hybridization probes to enrich exonic regions. Promoter, intronic, etc. regions are not assessed on our assay, but may contain variants that impact gene function.

Septo-optic dysplasia and Schizencephaly Panel (7 genes): COL4A1, EMX2, HESX1, OTX2, SHH, SIX3, SOX2

Specimen Requirements:

Blood: EDTA or ACD (Solution A or B):

  • Adult: 5 mL
  • Child: 5 mL
  • Infant: 2-3 mL

Saliva: 2 ORAgene™ Saliva Collection Kits (OGR-500) used according to manufacturer instructions.  Please contact KDL Client Services for a Saliva Collection Kit for patients that cannot provide a blood sample.

Assisted Saliva:
4 ORAgene™ Assisted Saliva Collection Kits (OGR-575) used according to manufacturer instructions.  Please contact KDL Client Services for an Assisted Saliva Collection Kit for patients that cannot provide a blood sample.

Skin Fibroblast:
Punch Biopsy (Cell cultures will be prepared at KDL and used for testing), or 2 T-25 confluent flasks.

DNA:
5-10µg at a minimum of 60-100ng/µL (DNA must be extracted in a CLIA-certified laboratory or a laboratory meeting equivalent requirements as determined by the CAP and/or CMS).

Prenatal

  • Direct Amniotic Fluid (10-20mL)
  • Direct CVS
  • Cultured Amniocytes (2 T-25 flasks)
  • Cultured CVS (2 T-25 flasks)
  • Cultured Fetal Tissue: Product of Conception (2 T-25 flasks)
  • Cord Blood ( 1-2mL)

Notice Regarding Molecular Genetic Testing on CVS or Amniotic Fluid Specimens:

  • Maternal cell rule-out testing will be performed on all prenatal specimens received. Please provide maternal blood in addition to the fetal specimen. Additional charges apply for the maternal cell rule-out test.
  • All genetic testing performed on Direct CVS or Amniotic Fluid specimens will be confirmed on cell cultures prepared by Knight Diagnostic Laboratories. Cell cultures will be prepared from the specimen received. Additional charges apply for confirmatory testing.
For routine testing of blood and saliva (or DNA extracted from them), KDL does NOT accept samples from patients within two (2) weeks of a packed cell/platelet transfusion or within four (4) weeks of a whole blood transfusion.  For extraordinary circumstances, where testing must be performed outside of the above windows, please contact our lab.


REQUISITION FORM MUST ACCOMPANY ALL SAMPLES.  Please include detailed clinical information, including ethnicity, clinical history, and family history.

Test Performed (Days):

Weekly

Turn Around Time:

8 weeks

Shipment Sensitivity Requirements:

  • Package and ship specimen to remain cold, but not frozen. 
  • Ship via overnight express, using the FedEx priority overnight label provided. 
  • Contact Client Services for shipping kits and instructions at (855) 535-1522.

References:

  1. Genetics Home Reference: SOD - https://ghr.nlm.nih.gov/condition/septo-optic-dysplasia

Additional Info: