Bottom line: There is a close association between JAK2 mutation (JAK2V617F) and myeloproliferative disorders, such as polycythemia vera, essential thrombocythemia, myelofibrosis with myeloid metaplasia.
Tefferi A, Gilliland DG. The JAK2V617F Tyrosine Kinase Mutation in Myeloproliferative Disorders: Status Report and Immediate Implications for Disease Classification and Diagnosis. Mayo Clin Proc. 2005;80(7):947-958.
Table 1 summarizes findings from 6 studies that document rate of JAK2 mutation in patients with polycythemia vera (65-97%), essential thrombocytopenia (23-57%), and myelofibrosis with myeloid metaplasia (35-50%)
Tefferi A, Vardiman JW. Classification and diagnosis of myeloproliferative neoplasms: The 2008 World Health Organization criteria and point-of-care diagnostic algorithms. Leukemia (2008) 22, 14–22
Table 2 includes diagnostic criteria for poycythemia vera, essential thrombocytopenia and primary myelofibrosis; presence of JAK2 mutation is a major criterion for diagnosing each of these conditions.