JAK2 (V617F)

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JAK2 (V617F)

Gene Symbol: JAK2

Chromosomal Locus: 9p24.1
 
Protein: Tyrosine-protein kinase JAK2
 
Pseudonyms: Janus kinase 2
 
TURNAROUND TIME: 8 days
 
 
 
2012 AMA Code: 81270
 
TESTING METHODOLOGY: V617F Mutation specific polymerase chain reaction (PCR) and fluorescent capillary electrophoresis
 
SPECIMEN REQUIREMENTS:
  • Collect: Prefer one 3ml bone marrow or 3ml whole blood EDTA (lavender top) tube.
  • Min. Collection: 0.7 ml bone marrow or whole blood.
  • Transport: Room Temp shipped regular next day air (No Saturday delivery; store specimen at 4°C and ship Monday).
  • Stability: Ambient: up to 7 days; Refrigerated: 2 weeks. Frozen: unacceptable
  • Unacceptable Conditions: Serum. Frozen or severely hemolyzed blood. Clotted blood.
A Molecular Genetics Laboratory Test Requisition must accompany the specimen. Contact the Molecular Laboratory at 918-502-1721 to obtain further information.
 
Note: Counseling and informed consent are recommended for genetic testing. A consent form is available as a resource but not required.
 
INTERPRETATIVE DATA:
 
Inheritance: Somatically acquired.
 
Disease Characteristics: The V617F mutation in the JAK2 gene is commonly found in acquired clonal myeloproliferative disorders. The detection of the mutation confirms the presence of a myeloproliferative disorder that has significant proliferative and survival advantages. Patients with the V617F mutation have a significantly longer duration of the disease with a higher rate of complications (fibrosis, hemorrhage and thrombosis).
 
Molecular Genetic Mechanism: The Val617Phe (V617F) mutation is in exon 14 at c.1849G>T. The mutation can be present as either a heterozygote or homozygote change.
 
Clinical Sensitivity: The V617F mutation is found in approximately 90% of Polycythemia Vera (PV), 50% of Essential Thrombocytopenia (ET), and 50% of Primary Myelofibrosis (PMF).
 
Analytical Sensitivity: 99%
 
Test Limitations: This test only detects the V617F mutation in exon 14 of the JAK2 gene. This test will not detect exon 12 mutations. Rare diagnostic errors can occur due to primer / probe site mutations or rare polymorphisms.
 
INDICATIONS FOR USE:
  • To identify the non-chronic myelogenous leukemia subgroup of myeloproliferative disorders.
  • Presence of JAK2 V617F mutation correlates with risk of thrombosis, marrow fibrosis and patient survival.
  • Identify patients who may respond to Jak2 tyrosine kinase inhibitors
ADDITIONAL REFERENCES: