Which of the following myeloproliferative neoplasms is associated with a JAK2 V617F mutation in nearly 100% of cases?
- A Essential thrombocythaemia
- B Polycythaemia vera ✓
- C Primary myelofibrosis
- D Chronic myeloid leukaemia
Correct answer: B. Polycythaemia vera
Explanation
JAK2 V617F mutation is present in approximately 95–97% of polycythaemia vera cases, making it virtually diagnostic in the appropriate clinical context (elevated haematocrit, low EPO). Essential thrombocythaemia and primary myelofibrosis each harbour JAK2 V617F in approximately 50–60% of cases; remaining cases carry CALR or MPL mutations. CML is driven by the BCR-ABL1 fusion gene and is not associated with JAK2 V617F.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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