Ann Lab Med.  2015 Jan;35(1):22-27. 10.3343/alm.2015.35.1.22.

Calreticulin Exon 9 Mutations in Myeloproliferative Neoplasms

• Ha JS
• Kim YK

• KMID: 2363143
• DOI: http://doi.org/10.3343/alm.2015.35.1.22

Abstract

BACKGROUND
Calreticulin (CALR) mutations were recently discovered in patients with myeloproliferative neoplasms (MPNs). We studied the frequency and type of CALR mutations and their hematological characteristics.
METHODS
A total of 168 MPN patients (36 polycythemia vera [PV], 114 essential thrombocythemia [ET], and 18 primary myelofibrosis [PMF] cases) were included in the study. CALR mutation was analyzed by the direct sequencing method.
RESULTS
CALR mutations were detected in 21.9% of ET and 16.7% of PMF patients, which accounted for 58.5% and 33.3% of ET and PMF patients without Janus kinase 2 (JAK2) or myeloproliferative leukemia virus oncogenes (MPL) mutations, respectively. A total of five types of mutation were detected, among which, L367fs*46 (53.6%) and K385fs*47 (35.7%) were found to be the most common. ET patients with CALR mutation had lower leukocyte counts and ages compared with JAK2-mutated ET patients.
CONCLUSION
Genotyping for CALR could be a useful diagnostic tool for JAK2-or MPL-negative ET or PMF patients. CALR mutation may be a distinct disease group, with different hematological characteristics than that of JAK2-positive patients.

Keyword

Calreticulin; JAK2; MPL; Myeloproliferative neoplasm

MeSH Terms

Adolescent
Adult
Aged
Aged, 80 and over
Amino Acid Sequence
Base Sequence
Calreticulin/*genetics
DNA Mutational Analysis
Exons
Female
Humans
Janus Kinase 2/genetics
Leukocyte Count
Male
Middle Aged
Molecular Sequence Data
Mutation
Myeloproliferative Disorders/diagnosis/*genetics/pathology
Receptors, Thrombopoietin/genetics
Young Adult
Calreticulin
Janus Kinase 2
Receptors, Thrombopoietin

Figure

• 

  Fig. 1 The five types of calreticulin mutations identified in this study. The arrowheads indicate the points where insertion or deletion occurred. Square boxes represent nucleotide sequences that were deleted or inserted.

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