MPL W515L mutation in pediatric essential thrombocythemia.

Essential thrombocythemia (ET) is extremely rare in the pediatric population. In most patients no molecular abnormality can be found, with about 40% of pediatric patients harboring a JAK2 V617F mutation. Another recurrent mutation, involving a W to L or K transversion at MPL codon 515, has been reported in about 3-8% of adult ET patients. Herein we describe this mutation in a pediatric patient.