Polycythemia vera in a 2-year-old child with a JAK2 exon 12 deletion

Polycythemia vera (PV) is a myeloproliferative neoplasm primarily characterized by erythrocytosis. PV incidence is exceedingly rare in the pediatric and adolescent population. In adult patients, approximately 96% are found to have a somatic mutation in exon 14 (JAK2 V617F) and 3% display a mutation in exon 12. We present a case of a 2-year-old female with symptomatic PV secondary to a deletion in exon 12 of JAK2, initially treated with phlebotomy and switched to PEG-IFNα-2a therapy. This therapy has been effective over 15 months with resolution of symptoms, reduced phlebotomy requirements, and minimal side effects.