title: [Role of the activating mutation Val617Phe of Janus kinase 2 gene in myeloproliferative diseases and significance of its detection].
abstract: The Val617Phe point mutation of Janus kinase 2 gene is believed to participate in the pathogenesis of myeloproliferative syndrome characterised by the clonal alteration of hematopoietic stem cells. According to current results, the frequency of Val617Phe activating mutation is around 80% in polycythaemia vera, 35% in essential thrombocythemia, and 50% in chronic idiopathic myelofibrosis. The diagnoses of polycythemia vera, essential thrombocythemia and idiopathic myelofibrosis were so far based on the exclusion of secondary factors as well as bone marrow biopsy histology. The goal of the present work was to establish simple molecular genetic techniques for the routine testing of Janus kinase 2 gene Val617Phe mutation, and to compare the clinical phenotypes of Val617Phe mutation positive and negative myeloproliferative syndromes. We employed the allele specific polymerase chain technique for detection of Val617Phe mutation in 252 patients with myeloproliferative syndrome. We measured Val617Phe frequency as 85,4% (117/137) in polycythemia vera, 56,6% (56/99) in essential thrombocythemia, and 87,5% (14/16) in idiopathic myelofibrosis. We found significantly elevated hemoglobin levels and white blood cell counts (measured at the time of diagnosis) in Val617Phe-positive polycythemia vera and essential thrombocythemia patient groups compared to Val617Phe-negative patients. However, the frequencies of splenomegaly and other complications (thrombosis, bleeding, transformation to acute leukemia) were not significantly different between the mutation-positive and negative groups. In conclusion, the non-invasive mutation analysis of the Janus kinase 2 Val617Phe is suitable for routine laboratory application and helps the differential diagnosis of myeloproliferative syndrome. Although the exact role of Val617Phe mutation testing has not yet been identified on the basis of a broad professional consensus, the testing is suggested in cases of erythrocytoses and thrombocytoses of unknown origin.
authors.affiliation: Országos Gyógyintézeti Központ, Molekuláris Diagnosztikai Osztály, Budapest, Hungary. andrikovics@kkk.org.hu
authors.forename: Hajnalka
authors.initials: H
authors.lastname: Andrikovics
authors.forename: Anikó
authors.initials: A
authors.lastname: Szilvási
authors.forename: Nóra
authors.initials: N
authors.lastname: Meggyesi
authors.forename: Viktória
authors.initials: V
authors.lastname: Király
authors.forename: Gabriella
authors.initials: G
authors.lastname: Halm
authors.forename: Sándor
authors.initials: S
authors.lastname: Lueff
authors.forename: Sarolta
authors.initials: S
authors.lastname: Nahajevszky
authors.forename: Gábor
authors.initials: G
authors.lastname: Mikala
authors.forename: Andrea
authors.initials: A
authors.lastname: Sipos
authors.forename: Nóra
authors.initials: N
authors.lastname: Lovas
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Csukly
authors.forename: Zoltán
authors.initials: Z
authors.lastname: Mátrai
authors.forename: Júlia
authors.initials: J
authors.lastname: Tamáska
authors.forename: Attila
authors.initials: A
authors.lastname: Tordai
authors.forename: Tamás
authors.initials: T
authors.lastname: Masszi
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D001853:Bone Marrow / Q000473:pathology; D005260:Female; D005786:Gene Expression Regulation; D005787:Gene Frequency; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009196:Myeloproliferative Disorders / Q000201:enzymology / Q000235:genetics*; D010641:Phenotype; D010649:Phenylalanine; D017354:Point Mutation; D011087:Polycythemia Vera / Q000235:genetics; D016133:Polymerase Chain Reaction; D055728:Primary Myelofibrosis / Q000235:genetics; D013922:Thrombocytosis / Q000235:genetics; D014633:Valine
chemical_list: D010649:Phenylalanine; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D014633:Valine