The prevalence of JAK2 exon12 mutations in Vietnamese patients with JAK2 V617F-negative polycythemia vera: frequent or rare?

Abstract

Purpose Polycythemia vera is a hematological malignancy characterized by the overproduction of red blood cells in the bone marrow. Pathogenesis of Polycythemia vera was thought to be caused by genetic mutations of the Janus kinase 2 (JAK2) gene, especially the JAK2 V617F and exon 12 mutations since those mutations were found frequently in the patients. The prevalence of JAK2 exon 12 mutations among Polycythemia Vera patients in Vietnam has not been studied yet. Objectives The overall study objective is to investigate the frequency of JAK2 exon 12 mutations among V617F-negative Polycythemia Vera patients in Vietnam. Methods In this study, the occurrence of these mutations was investigated in a clinical population of 76 Vietnamese Polycythemia Vera patients by PCR-RFLP and Sanger sequencing. Results The result showed that 53 of the patients were V617F-positive, and in 23 V617F-negative patients, only four individuals carried two JAK2 exon 12 mutations. Analysis by different in-silico tools predicted that all the two exon 12 mutations detected in this study (JAK2 c.1592A>G; p.H531R and c.1616A>G p.K539R) were benign. Conclusion These results suggested that the causative mutations in this V617F-negative subgroup might locate in another genetic region, and mutations in exon 12 might not be as common among the V617F-negative Polycythemia Vera patients as thought.