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Test Name:
Neurofibromatosis Type 1 (NF1) Deletion/Duplication

• SBMF No:
  44951
• Performance Lab Name:
  ARUP Laboratories
• Test Mnemonic:
  NF1 DELDUP
• ABN:
  Required – Not FDA-Approved
• CPT Code:
  83891; 83896x2; 83898x2; 83909x2; 83912; 83914x2
• LOINC Code:
  19146-0; 19146-0
• Ref Lab Test No:
  2001952
• Also See:
  44954 Legius Syndrome (SPRED1) Sequencing and (NF1) Sequencing Exon 22 (Exon 17)
• Spec Type:
  Whole blood
• Spec Container:
  Lavender top (EDTA) or pale yellow top (ACD-A or B) tube
• Pref Vol:
  3.0 mL
• Min Vol:
  1.0 mL
• Fasting:
  No
• Patient Prep:
  Counseling and informed consent are recommended for genetic testing
  Forms required:
  Informed Consent for Genetic Testing
  Patient History for Neurofibromatosis Type 1/Legius Syndrome
• Spec Collect:
  Routine venipuncture
• Spec Process:
  Gently invert tube to mix blood with the anticoagulant
  Do not centrifuge
  Do not remove plasma from cells
  Forward entire tube of unprocessed whole blood to the laboratory
• Spec Store Transport:
  Refrigerated
• Spec Stability:
  3 days room temperature (20-30°C)
  1 week refrigerated (2-8°C)
  Frozen (-20°C): Unacceptable
• Spec Reject:
  Frozen sample
• Methodology:
  Polymerase Chain Reaction (PCR)
  Multiplex Ligation-dependent Probe Amplification (MLPA)
• Reference Range:
  By report

  Interpretive Data:
  Background Information for Neurofibromatosis Type 1 (NF1) Deletion/Duplication:
  Characteristics: Neurofibromatosis type 1 (NF1) demonstrates extreme clinical variability. Features include: café au lait macules, axillary or inguinal freckling, dermal fibromas, Lisch nodules (iris hamartomas), optic glioma, specific osseous lesions such as tibial pseudarthrosis or sphenoid dysplasia, learning disabilities (50 percent), scoliosis, vertebral dysplasia, and somatic overgrowth. Large NF1 locus deletions increase the risk for neurofibroma development, cognitive abnormalities and malignant peripheral nerve sheath tumors (MPNST).
  Incidence: 1 in 3000.
  Inheritance: Autosomal dominant; de novo mutations occur in 50 percent of cases.
  Penetrance: 100 percent by adulthood.
  Cause: Deleterious NF1 mutations.
  Clinical Sensitivity: Approximately 5 percent of NF1 is caused by large NF1 locus deletions and 1 percent due to intragenic deletions.
  Methodology: Multiplex ligation-dependent probe amplification (MLPA) to detect large NF1 locus and intragenic deletions/duplications.
  Analytical Sensitivity and Specificity: 99 percent.
  Limitations: Rare diagnostic errors can occur due to probe site mutations. Breakpoints for large deletions/duplications will not be determined. NF1 base pair substitutions, small deletions/duplications, deep intronic, and regulatory region mutations will not be detected.

• Additional Test Info:
  

  Genetic Compliance Statement:
  The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing.

  Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

• Day Run:
  Varies
• Time Reported:
  Within 2 weeks
• Test Type:
  GENETIC