Ordering Recommendation

This is a second tier test and REQUIRES PERMISSION from ARUP's Genetic Counselor (800-242-2787, x2141) before ordering. Preferred initial test is the sequencing and deletion/duplication test.

Mnemonic
NF1 DELDUP
Methodology

Polymerase Chain Reaction/Multiplex Ligation-dependent Probe Amplification

Performed

Varies

Reported

14-21 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Lavender (EDTA), pink (K2EDTA) or yellow (ACD Solution A or B).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions
Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable

Reference Interval
Interpretive Data

Background Information for Neurofibromatosis Type 1 (NF1) Deletion/Duplication:
Characteristics:
Neurofibromatosis type 1 (NF1) demonstrates extreme clinical variability. Features include: cafe 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:
Pathogenic NF1 mutations.
Clinical Sensitivity:
Approximately 5 percent of NF1 is caused by large NF1 locus deletions and 2 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
: Diagnostic errors can occur due to rare sequence variations. Single base pair substitutions, small deletions/duplications, regulatory region mutations, and deep intronic mutations will not be detected. Large deletions/duplications of exons 11and 20 will not be detected. The breakpoints for large deletions/duplications will not be determined.

Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

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

Note
Hotline History
N/A
CPT Codes

81479

Components
Component Test Code* Component Chart Name LOINC
2001953 Neurofibromatosis 1 (NF1) DelDup Spec
2001954 Neurofibromatosis 1 (NF1) DelDup Interp
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • NF
  • NF1 Deletion/Duplication
  • Von Recklinghausen's Neurofibromatosis (NF1) Deletion/Duplication
Neurofibromatosis Type 1 (NF1) Deletion/Duplication