RNA-based NF1 Testing on Blood (NF1-R)
Information for Ordering
Acceptable Specimen Types
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- Fresh blood sample (3–6 mL EDTA; must be received within 60–72 hours of collection)
- Saliva and extracted DNA are not acceptable specimens.
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Whole blood specimens submitted for RNA-based testing must be received within 60–72 hours of collection to maintain lymphocyte viability.
Turnaround Time
Average turnaround time: 22 working days
Price, CPT Codes, and Z Code
- Institutional/self-pay price: $1,800 USD
- CPT codes: 88230, 81408, and 81479
- Z code: ZB6AF
Candidates for Testing
- Patients requiring the most sensitive and specific testing with the fastest turnaround time (for example, patients with an ongoing pregnancy).
- Non-founder patients:
- with clearly documented classic NF1;
- from a clinically documented multigeneration family (minimum three generations);
- who tested negative using the UAB MGL NF1-only NGS assay; or
- in whom a chromosomal translocation has been excluded by cytogenetic analysis. These patients will receive reflex RNA-based NF1 testing at no additional charge to identify possible deep intronic splice variants, Alu/LINE insertions, or other complex variants not detected by DNA-based testing.
Specimen Shipping and Handling
Please refer to the specimen requirements listed above.
All submitted specimens must be shipped at room temperature. Do not ship specimens on ice.
Specimens must be packaged to prevent breakage. Absorbent material must be included to contain liquids if breakage occurs. Specimens must also be shipped in double watertight containers, such as a specimen pouch placed inside the shipping company's diagnostic envelope.
To request a collection kit, please complete the Collection Kit Request Form .
Before shipping a specimen, please contact the UAB Medical Genomics Laboratory by email at medgenomics@uabmc.edu or by phone at 205-934-5562. Please provide the shipment date and package tracking number so the laboratory can help ensure proper and timely receipt.
Required Forms
About
Disorder Background
The NF1 gene, cloned in 1990, was the first gene within the RAS/MAPK pathway shown to be associated with an autosomal dominant disorder, Neurofibromatosis type 1 (NF1). NF1 affects approximately 1 in 3,000 individuals worldwide, with about half of affected individuals representing sporadic cases.
NF1 demonstrates considerable phenotypic variability and is a progressive disorder in which additional clinical manifestations develop with age. Although the NIH diagnostic criteria allow diagnosis in most classically affected patients, some individuals do not meet diagnostic criteria until later in childhood or adulthood. The NF1 variant spectrum is highly complex and includes numerous splice variants affecting exonic sequences as well as deep intronic variants that result in exonization of intronic sequences at the RNA level.
Test Description
The RNA-based NF1 testing on blood requires a fresh EDTA blood specimen received by the laboratory within 60–72 hours of collection.
DNA is extracted, and a short-term phytohemagglutinin-stimulated lymphocyte culture is established to provide RNA for analysis. The complete NF1 coding region is evaluated using complementary methodologies including RT-PCR, cDNA sequencing, microsatellite marker analysis, and MLPA copy number analysis. This comprehensive approach identifies the causative variant in approximately 95% of non-founder patients who meet NIH diagnostic criteria.
RNA-based NF1 testing enables identification of deep intronic splice variants through their effects on RNA splicing. These variants are generally not detectable using conventional exon-by-exon DNA sequencing approaches alone.
Over more than 15 years of comprehensive RNA-based NF1 testing, the UAB Medical Genomics Laboratory has identified more than 65 different locations harboring deep intronic splice variants. Together, these account for approximately 2.5% of all pathogenic NF1 variants identified in the UAB cohort. All currently known deep intronic splice variants have been incorporated into the laboratory's customized DNA-based NGS assays.
View references for this testing .
Other Related Test Options
- Next-Generation Sequencing and Deletion/Duplication Analysis of NF1 Only (NF1-NG)
- Next-Generation Sequencing and Deletion/Duplication Analysis of NF1 and SPRED1 (NFSP-NG)
- Expanded NF1 RASopathy Panel by Next-Generation Sequencing (RAS-NG)
- RNA-based NF1/SPRED1 Testing on Affected Tissues (NF14N/NF14C)
For more information, test requisition forms, or collection kits, please contact the UAB Medical Genomics Laboratory at 205-934-5562 or medgenomics@uabmc.edu.