Diagnostic Test Directory

Molecular Genetics Laboratory

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Neuroblastoma (ALK Known Mutation)

  • LIS Mnemonic: MBALKKM

    Collect

    Collect whole blood in a purple top (EDTA) tube (preferred). Extracted DNA is also acceptable.

    Volume Required

    5 ml whole blood or 1 ug extracted DNA

    Minimum Required

    3 ml whole blood

    Transport

    Refrigerate sample until shipment. Send the sample at room temperature with overnight delivery for receipt Monday through Friday within 24 hours of collection.

    Stability

    Whole blood can be refrigerated until shipment.

    Unacceptable conditions

    Heparinized specimens, severely hemolyzed specimens, frozen, clotted or possibly commingled specimens, blood in non-sterile or leaky containers, mislabeled or inappropriately labeled specimens.

    Specimen Handling

    Do not heat, freeze or centrifuge blood before shipment. Refrigerate sample until shipment.

Days Performed

Mon - Fri 9:00am to 4:00pm

Reported

2-3 weeks

CPT

81479

Disease Information

Clinical Features:

Neuroblastoma is a cancer of early childhood that arises from the developing autonomic nervous system and accounts for 15% of childhood cancer mortality. Neuroblastoma usually occurs sporadically but a subset of neuroblastoma cases are inherited in an autosomal dominant manner. Heritable mutations in the anaplastic lymphoma kinase (ALK) oncogene have been shown to be the main cause of familial neuroblastoma.

Molecular Genetics:

ALK maps to chromosome 2p23 and is a tyrosine kinase transmembrane receptor with homology to neutrophin receptors and the MET proto-oncogene. Germline missense mutations have been identified mostly in the tyrosine kinase domain of the ALK gene in hereditary neuroblastomas. These missense variants are predicted to be activating mutations that result in constitutive phosphorylation of the kinase domain. Somatically acquired missense mutations in the kinase domain of the ALK gene have also been identified.

Test Methods:

Sequence analysis of the mutation previously identified in a family member will be performed.

Detection Rate:

The analytical sensitivity is close to 100% for germline point mutations by DNA sequencing.

Related Tests:

Prenatal testing (for germline mutations) is available to individuals who are confirmed carriers of a mutation. Please contact the laboratory director to discuss appropriateness of testing prior to collecting a prenatal specimen.

Results:

Test results with interpretation will be mailed and/or faxed to the referring physician following completion of the test. Additional reports will be provided as requested.

Utility:

The clinical utility of the assay is in assessing the risk to other first degree relatives by genotyping at risk family members for already identified mutations, and establishing the need for continued clinical surveillance of the patient for the purpose of early detection of tumors.

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