|NRAS Gene Sequencing||
Analysis of the entire coding region: Sequence analysis
Polymerase chain reaction (PCR)
|Container Type||Container Size||Specimen Volume|
Purple tube (EDTA)
|4 mL||4 mL-8 mL|
Room temperature - 24 hour(s)
Refrigerated - 72 hour(s)
- Do not freeze
- Do not centrifuge
- Keep at room temperature or refrigerate
Reasons for Rejection
- Centrifuged specimen
- Clotted specimen
- Frozen specimen
- Wrong collection tube
- Delayed or improper handling
Please click on the Lab Form Link in the Forms Section to print and complete the Genetic Test Requisition Form. Submission of completed Genetic Test Requisition Form is required, and submission of informed consent form is recommended but not required.
This test is a full gene sequencing of the NRAS gene, which is associated with a group of disorders called Noonan spectrum disorders (RASopathies). RASopathies include Noonan syndrome, Costello syndrome, cardio-facio-cutaneous (CFC) syndrome, and LEOPARD syndrome. They are related genetic disorders caused by mutations in the genes that encode proteins in RAS-mitogen-activated protein kinase (MAPK) signal transduction pathway. These four disorders have molecular and phenotypic overlap; however, each also has a distinct set of defining characteristics. Noonan syndrome is caused by mutations in PTPN11 (50%), SOS1 (10%), KRAS (<5%), RAF1 (3%-17%) and NRAS and SHOC2 (each 1% or less). Costello syndrome is associated with mutations in HRAS (80%-90%). CFC syndrome is caused by mutations in BRAF (75%-80%), MAP2K1 (MEK1) and MAP2K2 (MEK2) (10%-15%), and KRAS (<5%). LEOPARD syndrome is caused by mutations in PTPN11 (90%) and RAF1 (<10%). It is likely that additional undefined genes, possibly related to RAS-MAPK signal transduction, are associated with these disorders. Thus, a negative result does NOT rule out any given clinical diagnosis.
For comprehensive RASopathy genetic evaluation, NGS RASopathy Panel (Test Code: NGSRP) is recommended, which is a full gene sequencing panel for 14 genes associated with RASopathy disorders. Targeted NRAS mutation analysis is available for family members when familial mutation is known (see Test Code: FMLIS).