Ruxolitinib in a Child With JAK2 Exon 12 Mutant Polycythemia Vera

Background:Polycythemia Vera (PV) is a well-defined disorder of erythroid hyperproliferation that can result in life-threatening thromboembolic and hemorrhagic events. It is most prevalent in adults and is caused by mutations in Janus Kinase 2 (JAK2). Predominantly, PV is caused by a JAK2V617F mutation on exon 14. Observations:A rare case of PV in a 9-year-old, driven by an uncommon, p.Glu543_Asp544del, JAK2 exon 12 mutation. Despite management with phlebotomy, aspirin and hydroxyurea, the patient suffered a dural sinus venous thrombosis, prompting a change in therapy to Ruxolitinib. Conclusions:This is the first description of the successful use of ruxolitnib to treat a pediatric patient with PV caused by a JAK2 exon 12 mutation.