Clinical and Laboratory ObservationsRuxolitinib in a Child With JAK2 Exon 12 Mutant Polycythemia VeraStoops, Katie MS4*; Kuril, Sandeepkumar MD† Author Information *College of Medicine †Division of Pediatric Hematology-Oncology, Department of Pediatrics, Shawn Jenkins Children’s Hospital, Medical University of South Carolina, Charleston, SC K.S. and S.K. contributed equally to this work. The authors declare no conflicts of interest. Reprints: Sandeepkumar Kuril, MD, Department of Pediatrics, Division of Pediatric Hematology-Oncology, Shawn Jenkins Children’s Hospital, 10 McClennan Banks Dr, Charleston, SC 29425 (e-mail: [email protected]). Journal of Pediatric Hematology/Oncology ():10.1097/MPH.0000000000002549, September 9, 2022. | DOI: 10.1097/MPH.0000000000002549 Buy PAP Metrics Abstract 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. Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.