Background: In recent years, a somatic point mutation in the Janus Kinase 2 (JAK2) gene (1849 G→T, V617F) has been reported to occur in over 90% of patients with polycythemia vera (PV). Another JAK2 mutation in exon 12 had been described and shown capable of activating erythropoietin signaling pathways. Objective: In this study, we aimed to determine the frequency of Jak2 mutations (JAK2V617F and JAK2 exon 12) as well as their relationships with hematological parameters in Sudanese patients with myeloproliferative disorders (MPD). A comparison with findings of published studies from other geographic regions was included. Materials and Methods: From each of a total of 83 polycythaemia patients, six milliliters (ml) of venous blood were collected and processed for molecular analysis and measurement of serum erythropoietin level by enzyme-linked immunoassay (ELISA). The JAK2 V617F mutation was determined using an allele-specific competitive blocker (ACB) -PCR assay and High Resolution Melting (HRM) analysis was applied for the JAK2 exon 12 mutation. Results: According to patients’ history and the results for EPO levels, nine (10.7 %) out of 83 patients were found to have secondary polycythaemia and 74 (89.3%) PV. The overall frequency of the 2 JAK2 mutations was 94.6% in our Sudanese PV patients, JAK2V617F being found in 91% and JAK2 exon 12 mutations in 8.1%.Conclusion: In summary JAK2 V617F and JAK2 exon 12 mutations are very common in Sudanese PC cases.
The co-occurrence of JAK2 V617F mutation with BCR-ABL reciprocal translocation is uncommon. We report a 60-year-old man who initially presented with phenotype of polycythemia vera (PV), which evolved into chronic myeloid leukemia and back to PV once treatment with imatinib was commenced. JAK2 V617F mutation and BCR-ABL fusion transcripts were detected in the initial sample. However, JAK2 V617F alleles diminished when BCR-ABL mRNA burden increased and reappeared once the patient was commenced on imatinib. The dynamic interaction between JAK2 V617F and BCR-ABL implies that two independent clones exist with the JAK2 V617F clone only achieving clonal dominance when BCR-ABL positive clones are suppressed by imatinib.