• Test Code:
    1001
  • Department:
  • Test Synonyms:
    Achromatopsia SequencingAutosomal Recessive Stargardt Disease Pingelapese AchromatopsiaPingelapese Blindness; Rod Monochromatism 2
  • CPT Code(s):
    81479
Background:

Achromatopsia is characterized by reduced visual acuity (<0.1 or 20/200), nystagmus, sensitivity to light, small central scotoma, eccentric fixation and reduced or complete loss of color discrimination.  The diagnosis is based on color vision testing, electroretinography, and fundus examination.  Known genetic causes of this disorder are mutations in the cone cell subunits alpha, CNGA3, and beta, CNGB3.  Mutations in CNGB3 account for 50% of the affected individuals1,2, and 25% harbor mutations in CNGA33,4.

Reasons for Referral:

  • Confirmation of clinical diagnosis in patients with classical or atypical Achromatopsia.
  • Carrier testing of family members of Achromatopsia patients with known mutations.

Methodology:

Next generation sequencing will analyze the exons or coding regions of 2 Achromatopsia-associated genes using Illumina NextSeq 500 technology.  Samples are prepared 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.

The 2 Achromatopsia-associated genes are listed below:
CNGA3, CNGB3

Specimen Requirements:

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

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

Saliva: 2 ORAgene Saliva Kit(s) (OGR-500)
Skin Fibroblast: Punch Biopsy, or 2 T-25 confluent flasks
Prenatal:

  • Direct Amniotic Fluid (10-20mL)
  • Direct CVS
  • Cultured Amnio or CVS (2-T25 flasks)

DNA: 1-2µg at a minimum of 50-100ng/µL (DNA must be extracted in a CLIA-certified laboratory or a laboratory meeting equivalent requirements as determined by the CAP and/or CMS)

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 Direct 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, saliva and buccal swabs, 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.

A 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:

21 days

Shipment Sensitivity Requirements:

  • Keep specimen cold during transit, but do not ship on dry ice.
  • Please use the cold pack provided in the KDL shipping kit.
  • Contact Client Services at (855) 535-1522 for shipping kits and instructions.
  • Ship the specimen overnight express, using the FedEx priority overnight label provided.

References:

  1. Kohl, et al. Eur J Hum Genet 13, 302-308 (2005).
  2. Kohl, et al. Hum Mol Genet 9, 2107-2116 (2000).
  3. Wissinger, et al. Am J Hum Genet 69, 722-737 (2001).
  4. Kohl, et al. Nat Genet 19, 257-259 (1998).
  5. Human Genome Mutation Database: http://www.hgmd.cf.ac.uk/ac/gene.php?gene=CNGA3.

Additional Info:

Prior to any genetic testing we recommend genetic counseling. To receive forms and information about prenatal diagnostic testing, please contact Client Services at (855) 535-1522.

The Knight Cancer Institute at Oregon Health & Science University is a pioneer in the field of precision cancer medicine. The institute's director, Brian Druker, M.D., helped prove it was possible to shut down just the cells that enable cancer to grow. This breakthrough has made once-fatal forms of the disease manageable and transformed how cancer is treated. The OHSU Knight Cancer Institute is the only National Cancer Institute-designated Cancer Center between Sacramento and Seattle – an honor earned only by the nation's top cancer centers. It is headquarters for one of the National Cancer Institute's largest research collaboratives, SWOG, in addition to offering the latest treatments and technologies as well as hundreds of research studies and clinical trials.

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