Background: The JAK2 V617F mutation has been noted in a majority of cases of polycythemia Vera, essential thrombocythemia, and primary myelofibrosis patients but occurs less frequently in myelodysplastic syndrome (MDS) about 5% of the cases; In Morocco, the Incidence of MDS will increase significantly in our country, MDS will be the disease of national public health. The aim of the current study was to determine prevalence of JAK2V617F mutation in Moroccan patients with MDS, and to compare characteristics of JAK2 mutation group to JAK2 wild type group. Methods: This prospective study included all patients who are newly diagnosed with MDS in hematology department 20 August hospital Casablanca from January 2014 to December 2015 period. The criteria of diagnostic were based on WHO classification, using blood, bone marrow analysis and karyotype. Group risk were defined according to the international prognostic scoring system (IPSS). Data obtained from JAK2 V617F mutation analysis and cytogenetic study as well as complete blood count and clinical data were analyzed. Results: we analyzed the JAK2 V617F mutational status in 49 MDS patients with sex ratio F/M at 1.3. The median age was 63 years old. The JAK2 V617F was present in 8% of cases. About mutated group, the median age was 74 years old. The platelet count was higher than 450000/mm³ in 2 cases, leukocyte count was also higher than 13000/mm³ in one case, hemoglobin count increased in 2 cases. Clinically one patient presented splenomegaly. According to WHO classification in this group mutated, one patient presented refractory anemia with excess blast (RAEB-1), one patient with MDS-U, and two cases of RCMD. About cytogenetic analysis the most common feature was normal karyotype and score intermediate 1 of IPSS risk score. Conclusion: The JAK2 V617F mutation is associated with older age and high platelet count with characteristics of MPN, the main cytologic and genetic features are the frequency of RCMD with normal Karyotype and intermediate prognosis, but further study are required to confirm this specificity.
