Research Article Thrombophilic Risk of Factor V Leiden, Prothrombin G20210A, MTHFR, and Calreticulin Mutations in Essential Thrombocythemia Egyptian Patients Mohamed S. El-Ghonemy , 1 Solafa El Sharawy, 1 Maryan Waheeb Fahmi, 2 Shaimaa El-Ashwah, 3 May Denewer, 3 and MA El-Baiomy 2 1 Hematology Unit, Clinical Pathology Department, Mansoura University Faculty of Medicine, Mansoura, Egypt 2 Medical Oncology Unit, Oncology Center, Mansoura University, Faculty of Medicine, Mansoura, Egypt 3 Clinical Hematology Unit, Oncology Center, Mansoura University, Faculty of Medicine, Mansoura, Egypt Correspondence should be addressed to Mohamed S. El-Ghonemy; mohsabali@yahoo.com Received 18 September 2019; Revised 4 December 2019; Accepted 6 February 2020; Published 30 March 2020 Academic Editor: Bashir A. Lwaleed Copyright © 2020 Mohamed S. El-Ghonemy et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Objectives. Essential thrombocythemia (ET) is one of the myeloproliferative neoplasms characterized by a sustained elevation of platelet numbers with a tendency for thrombosis and hemorrhage. e aim of this work is to establish the relation between calreticulin, factor V Leiden, prothrombin G20210A, and MTHFR mutations in ET patients and the thrombotic risk of these patients. Methods. is study was carried out on 120 ETpatients and 40 apparently healthy individuals as a control group. Results. ere were increases in WBCs, PLTcounts, PT, fibrinogen concentration factor V Leiden, and MTHFR mutation in ETpatients as compared to the control group (P < 0.05). Also, there were increases in WBCs, PLT counts, and hematocrit value in thrombosed ETpatients as compared to the nonthrombosed ones (P < 0.05). On the contrary, there was no significantly statistical difference in ETpatients with JAK2 V617F positive mutation versus the JAK2 negative group (P > 0.05) and in patients with cardiovascular risk factors versus patients with noncardiovascular risk factors (P > 0.05). ET patients with factor V Leiden, prothrombin gene, and CALR mutations were more prone to thrombosis (odds ratio 5.6, 5.7 and 4.7, respectively). On the contrary, JAk2V 617F and MTHFR mutations have no effect on the thrombotic state of those patients. Conclusion. ere is a significant increase risk of thrombosis in ET patients with CALR mutation, thrombophilic mutations, as well as factor V Leiden and prothrombin gene mutation with a risk of developing leukemic transformation. 1.Introduction Essential thrombocythemia (ET) is one of the “myeloprolif- erative neoplasms” (MPNs) characterized by clonal overpro- duction of one or more blood cell lines. ETis characterized by a sustained elevation of platelet number with a tendency for thrombosis and hemorrhage [1]. ETmay be asymptomatic or it may be presented by vascular occlusive events and hemor- rhages [1, 2]. e most common molecular marker of these diseases is JAK2 V617F mutation present in 50–70% and calreticulin (CALR), a multifunctional calcium-binding pro- tein, mutation present in 15–24% [1]. rombophilia is common in ET patients which may be genetic or acquired. e pathogenesis of thrombosis in ET is complex and not yet fully understood [2]. Several defects have been described, including an autonomous production of platelets unregulated by the physiologic feedback mechanism to keep the count within the reference range [3]. Also, in ET, there were increased sensitivities to cytokines (e.g., interleukin-3 (IL-3)) and decreased inhibition to platelet-inhibiting factors (e.g., transforming growth factor (TGF) beta), leading to hyperaggregation [4]. However, Pearson [5] reported that platelet count per se does not correlate with thrombotic incidence. Hindawi Advances in Hematology Volume 2020, Article ID 7695129, 6 pages https://doi.org/10.1155/2020/7695129