Journal of Thrombosis and Thrombolysis

, Volume 45, Issue 3, pp 457–462 | Cite as

A rare CALR variant mutation and a review of CALR in essential thrombocythemia

  • Robert DiepEmail author
  • Ara Metjian


Essential thrombocythemia (ET) is an indolent myeloproliferative neoplasm characterized by megakaryocyte hyperplasia, thrombocytosis, thrombotic and hemorrhagic complications, and potential transformation into myelofibrosis and acute myeloid leukemia. The vast majority of cases are driven by a somatic mutation in JAK2, CALR, or MPL. CALR, a gene that codes for the calcium-binding chaperone calreticulin, is the predominant mutation in patients with non-mutated JAK2 essential thrombocythemia, accounting for 20–25% of the overall somatic mutation frequency in ET. In this brief review of ET, we introduce a rare CALR mutation through a case presentation of a 58-year-old man with diffuse pulmonary emboli in the setting of thrombocytosis. We subsequently characterize the main types of CALR mutations and their value in diagnosis and prognosis of disease course, and lastly discuss the current clinical approach to ET.


CALR Thrombocytosis Essential thrombocythemia Myeloproliferative disorders 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical approval

In keeping with the Duke IRB policy, the review of medical records for publication of a single case report is not considered to be research involving human subjects, and therefore such a report does not require IRB review and approval.


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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of MedicineDuke University Medical CenterDurhamUSA
  2. 2.Division of Hematology, Department of MedicineDuke University Medical CenterDurhamUSA
  3. 3.Duke University Health SystemDurhamUSA

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