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Characterization of a patient with atypical amegakaryocytic thrombocytopenia
Author(s) -
Kanaji Sachiko,
Kanaji Taisuke,
Migita Masahiro,
Kunishima Shinji,
Kunicki Thomas J.,
Okamura Takashi,
Izuhara Kenji
Publication year - 2008
Publication title -
european journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.904
H-Index - 84
eISSN - 1600-0609
pISSN - 0902-4441
DOI - 10.1111/j.1600-0609.2008.01029.x
Subject(s) - gpvi , mutation , platelet , cancer research , gene , phenotype , thrombopoietin , janus kinase 2 , phosphorylation , glycoprotein , medicine , platelet membrane glycoprotein , tyrosine phosphorylation , immunology , microbiology and biotechnology , biology , genetics , haematopoiesis , stem cell
We report a 6‐year‐old girl with amegakaryocytic thrombocytopenia, the first case of this rare congenital disorder not to have an MPL gene mutation. Although no mutations were identified in MPL , Mpl protein was absent in the platelets and TPO induced phosphorylation of the Janus tyrosine kinase 2 (Jak2) was not detected. In addition to the defect of Mpl, the patient demonstrated markedly reduced expression of glycoprotein VI (GPVI) in contrast to normal expression of other platelet‐specific proteins GPIbα, GPIbβ, and GPIIb. To explore the causes for the absence of Mpl, the entire coding resion of Jak2 and AML1 were sequenced and no mutations were identified. To our knowledge, this is the first report that describes a case of amegakaryocytic thrombocytopenia that is not caused by a mutation in MPL and demonstrates the severe impairment of GPVI expression on platelets.