Acceptable test to confirm a suspected diagnosis of neurofibromatosis type 1 (NF1) in individuals not meeting NIH clinical criteria.
- Patient Preparation
- Lavender (K2EDTA), Pink (K2EDTA), or Yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 2 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 1 week; Refrigerated: 1 month; Frozen: 6 months
Characteristics: Neurofibromatosis ty1 (NF1) demonstrates extreme clinical variability. Features include: cafe au lait macules, axillary and 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 77-86 percent of causative mutations are detected by sequencing.
Methodology: Bidirectional sequencing of the entire coding region and intron-exon boundaries of the NF1 gene.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: Diagnostic errors can occur due to rare sequence variations. Regulatory region mutations, deep intronic mutations, and large deletions/duplications will not be detected. Mutations in genes other than NF1 are not evaluated. This assay is not designed to detect somatic variants associated with malignancy. Interpretation of this test result may be impacted if the patient has had an allogeneic stem cell transplantation.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2007160||Neurofibromatosis I (NF1) Seq Specimen|
|2007161||Neurofibromatosis 1 (NF1) Seq Interp|
- NF1 sequencing assay
- Von Recklinghausen's Neurofibromatosis (NF1) Sequencing