title: Thrombocytosis in an infant with high thrombopoietin concentrations.
abstract: Patients with essential thrombocythemia (ET) usually have normal thrombopoietin (TPO) concentrations because of negative feedback from thrombocytosis. TPO mutations in familial ET cases result in increased translation efficiency with excessive TPO stimulation and thrombocytosis. The authors describe an infant with a high platelet count (1300 x 103/mm3) and an elevated TPO concentration who was successfully treated with anagrelide. Sequencing of TPO revealed no genetic cause. This case may represent a case of atypical ET in which thrombocytosis results from TPO stimulation rather than clonal proliferation. Measuring TPO concentrations may be warranted for children with unexplained extreme thrombocytosis.
authors.affiliation: Department of Hematology-Oncology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.
authors.forename: Jane
authors.initials: J
authors.lastname: Hankins
authors.forename: Paula
authors.initials: P
authors.lastname: Naidu
authors.forename: Martha
authors.initials: M
authors.lastname: Rieman
authors.forename: Winfred
authors.initials: W
authors.lastname: Wang
authors.forename: Kenneth
authors.initials: K
authors.lastname: Kaushansky
authors.forename: Carlos
authors.initials: C
authors.lastname: Rodriguez-Galindo
mesh_terms: D001792:Blood Platelets / Q000737:chemistry; D005260:Female; D006801:Humans; D007223:Infant; D010976:Platelet Count; D013922:Thrombocytosis / Q000097:blood*; D013926:Thrombopoietin / Q000097:blood* / Q000235:genetics; D015854:Up-Regulation
chemical_list: D013926:Thrombopoietin