JAK2 V617F mutation is uncommon in patients with the 3q21q26 syndrome.

The 3q21q26 syndrome is recognized as a distinct clinicopathologic entity. Patients have a myeloid neoplasm associated with 3q21q26 cytogenetic abnormalities and present with anemia, leukopenia, and either thrombocytosis or a normal platelet count associated with dysplasia. To determine if JAK2 V617F mutation is implicated in the abnormal thrombopoiesis of the 3q21q26 syndrome, we analyzed bone marrow samples of 12 patients, including 10 patients with acute myeloid leukemia and 2 patients with a myelodysplastic syndrome, associated with either inv(3)(q21;q26) or t(3;3)(q21;q26). The platelet count ranged from 142 to 597 x 10(3)/microL. Using polymerase chain reaction and pyrosequencing assays, no evidence of JAK2 V617F was identified in 11 of 12 cases. A JAK2 V617F mutation was identified in one patient who had acute myeloid leukemia with concurrent mast cell disease. Separate DNA analysis of myeloblasts and mast cells after laser capture microdissection confirmed that JAK2 V617F was present in both components. We conclude that JAK2 V617F mutation is uncommon in the 3q21q26 syndrome and that its presence may indicate an unusual coexistence of a myeloproliferative neoplasm.