Which of the following is a major criteria for diagnosis of poycythemia vera:

Answer is A (Presence of JAK-2 mutation) Presence of JAK-2 mutation is a Major criterion fir diagnosis of polycythemia Vera according to the proposed new WHO criteria for the diagnosis of Polycythemia Vera. Low Erythropoetin levels, Thrombocytosis and increased LAP scores are all minor criteria for diagnosis of polycythemia Vera. JAK-2 Mutation and Polycythemia Vera JAK-2 is a member of an evolutionarily well conserved, non receptor tyrosine kinase family and serves as the cognate tyrosine kinase for the erythropoietin receptors A mutation in the tyrosine kinase JAK-2 appears to have a central role in the pathogenesis of PV by causing constitutive activation of the kinase The presence of JAK -2 mutation thus allows for the exclusion of a reactive erythrocytosis. The 2001 WHO criteria for diagnosis of PV were however developed prior to the discovery of this impoant mutation and hence revised WHO criteria have been developed that include presence of JAK-2 mutation as a major criterion for diagnosis of PV Note : Although presence of JAK-2 mutation is a major criterion for diagnosis of PV, the presence of JAK-2 mutation alone is not diagnostic of PV. JAK-2 mutations may also be seen in other myeloproliferative disorders such as Essential Thrombocytosis (ET) and Chronic Idiopathic Myelojlbrosis (CIMF). Various major and minor criteria used for the diagnosis of polvcythemia vera in various classification systems (WHO criteria (revised and old )/ Polvcythemia vera study group criteria) Major Minor * JAK2 V617F mutation * Thrombocytosis (> 400 x 109/L) * Hemoglobin >18.5 g/dL in men, 16.5 g/dL in * Leucocytosis (WBC > 12 x 109/L) women * Increased leukocyte alkaline phosphatase (LAP > 100U) * Increased red blood cell mass * Increased serum B12/binders * Splenomegaly (B12 > 900 pg/ml; unbound B12 binding capacity> 2200 pg/ml) * Clonal genetic abnormality other than * Low serum erythroprotein levels. Philadelphia chromosome or BCR/ABL in marrow * Panmyelosis with prominent erythoid and megakaryocytic * Endogenous erythroid colony formation in vitro hyperplasia on bone marrow biopsy. * Normal aerial 02 saturation (>92%) Revised WHO criteria (Proposed) for the diagnosis of Polycythemia vera Revised WHO criteria (Proposed) for the diagnosis of Polycythemia vera Major Criteria Hemoglobin > 18.5 g/dl in men, > 16.5 g/dl in women or evidenced on increased red cell volume Presence of JAK2 mutation Minor Criteria Hypercellular bone marrow biopsy with panmyelosis with prominent erythroid, granulocytic, and megakaryocytic hyperplasia Low serum erythropoietin level Endogenous erythroid colony formation in vitro. WHO Criteria (Previous) for the diagnosis of Plvcythemia vera Major Criteria Red blood cell mas > 25% above mean normal predicted value, or Hb > 18.5 g/dl in men, 16.5 g/dI in women. Splenomegaly on palpation Clonal genetic abnormality other than Philadelphia chromosome or BCR/ABL in marrow. Endogenous erythroid colony formation in vitro Minor Criteria Thrombocytosis > 400 x 109/L WBC > 12 x 109/L Panmyelosis with prominent erythroid and megakaryocytic hyperplasia on bone marrow biopsy. Low serum erythropoietin levels. WHO Criteria for the diagnosis of Plycythemia Vera (Prior to the proposed new criterion)