title: Thrombocythemia and polycythemia in patients younger than 20 years at diagnosis: clinical and biologic features, treatment, and long-term outcome.
abstract: Sixty-four patients < 20 years of age, investigated for a suspicion of Philadelphia-negative myeloproliferative disease (MPD), were retrospectively evaluated to characterize the different forms and to examine the treatments used and long-term outcome. JAK2 mutations, endogenous erythroid colony growth, and clonality were investigated in 51 children. Mutations of thrombopoietin, the thrombopoietin receptor (MPL), and the erythropoietin receptor and mutations of other genes involved in the pathogenesis of MPD were investigated in JAK2 wild-type patients. Based on our criteria for childhood MPD, we identified 34 patients with sporadic thrombocythemia (ST), 16 with hereditary thrombocytosis (HT), 11 with sporadic polycythemia (SP), and 3 with hereditary polycythemia (HP). JAK2(V617F) mutations were present in 47.5% of ST and in no HT. The MPL(S505A) mutation was detected in 15/16 HT patients and in no ST (P < .00001). The JAK2(V617F) mutation occurred in 27% of SP patients diagnosed according to the Polycythemia Vera Study Group or World Health Organization 2001 criteria. Children with ST received more cytoreductive drugs than those with HT (P = .0006). After a median follow-up of 124 months, no patient had developed leukemia or myelofibrosis and 5% had thrombosis; the miscarriage rate in thrombocythemic patients was 14%. The low complication rate in our population suggests that children with MPD may be managed by tailored approaches.
authors.affiliation: Department of Cellular Biotechnologies and Hematology, Sapienza University, Rome, Italy. giona@bce.uniroma1.it
authors.forename: Fiorina
authors.initials: F
authors.lastname: Giona
authors.forename: Luciana
authors.initials: L
authors.lastname: Teofili
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Moleti
authors.forename: Maurizio
authors.initials: M
authors.lastname: Martini
authors.forename: Giovanna
authors.initials: G
authors.lastname: Palumbo
authors.forename: Angela
authors.initials: A
authors.lastname: Amendola
authors.forename: Maria Gabriella
authors.initials: MG
authors.lastname: Mazzucconi
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Testi
authors.forename: Patrizia
authors.initials: P
authors.lastname: Pignoloni
authors.forename: Sonia Maria
authors.initials: SM
authors.lastname: Orlando
authors.forename: Sara
authors.initials: S
authors.lastname: Capodimonti
authors.forename: Mauro
authors.initials: M
authors.lastname: Nanni
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Leone
authors.forename: Luigi Maria
authors.initials: LM
authors.lastname: Larocca
authors.forename: Robin
authors.initials: R
authors.lastname: Foà
mesh_terms: D000293:Adolescent; D019943:Amino Acid Substitution; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D053614:Janus Kinase 2 / Q000235:genetics; D008297:Male; D009154:Mutation; D011086:Polycythemia / Q000150:complications / Q000188:drug therapy* / Q000235:genetics; D011247:Pregnancy; D011250:Pregnancy Complications, Hematologic; D011256:Pregnancy Outcome; D053628:Receptors, Thrombopoietin / Q000235:genetics; D012189:Retrospective Studies; D013920:Thrombocythemia, Essential / Q000150:complications / Q000188:drug therapy* / Q000235:genetics; D013922:Thrombocytosis / Q000150:complications / Q000188:drug therapy* / Q000235:genetics; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D053628:Receptors, Thrombopoietin; C082218:MPL protein, human; D053614:Janus Kinase 2