PB2239 COEXISTENCE OF β‐THALASSEMIA WITH IVS‐2‐654 MUTATION AND ESSENTIAL THROMBOCYTHEMIA

Background: Beta‐thalassemia (β‐thalassemia) is characterized by abnormalities in the synthesis of the hemoglobin subunit beta(hemoglobin beta chain), resulting in anemia of different degrees of severity1.ET is a chronic MPN, characterized by the clonalproliferation of megakaryocytes in the bone marrow and a high platelet count in the peripheral blood2. JAK2/V617F mutationscreening is part of the diagnostic workup for ET, according to the World Health Organization. The combination ofmyeloproliferative neoplasias (MPN) and β‐thalassemia is extremely unusual. Only several cases of concurrent β‐thalassemia andpolycythemia vera (PV) have been reported thus far in the literature3 Aims: ET in β‐thalassaemic patients has not been previously described. To our knowledge, this is the first report on coexistence of β‐thalassemia and ET. Methods: A 24‐year‐old female, diagnosed with β‐thalassemia and underwent splenectomy in childhood, was evaluated for alifelong history of anemia and thrombocytosis. The outcome of her genetic test was shown in figure 1the mutant site of beta‐globingene is in IVS‐2‐654which was reported as a common type of beta‐thalassemia in Chinese Results: A research group investigated the status of thalassemia in Guangxi, China. The study shows that IVS‐2‐654 mutationsaccount for 5.8% of β‐thalassemia 7whereas another study found Cd 41/42 (‐TTCT) and IVS 2‐654 (C‐T) mutations were mostcommon among the Chinese (79.1%)8. Her blood routine monitoring results in moderate anemia and high platelet count. Hercomplete blood count showed white blood cells, 9.6 × 10 12/L; red blood cells, 3.61 × 1012/L; hemoglobin, 85 g/L; mean corpuscularvolume, 78.6fL; and platelets, 393 × 109/L. During the follow‐up, her platelet counts had risen to as high as 650 × 109/L. Measures ofinflammation including erythrocyte sedimentation rate and C‐reactive protein were normal and no clinical signs of infection weredetectable to explain marked thrombocytosis. A myeloproliferative disorder was considered. To confirm the disease, a bone marrowbiopsy were performed, showing prominent conspicuous megakaryocyte proliferation in clusters and mild bone marrow reticulinfibrosisFig. 2. Conventional cytogenetics revealed a normal karyogram, and molecular study showed the absence of BCR‐ABLtranscript and presence of JAK2/V617F mutation. The diagnosis was established by the presence of the JAK2/V617F mutation, afinding present in approximately 57% of essential thrombocythemia (ET) cases9. In addition, Next‐generation sequencing showed atotal of 114 variants with 47.0% of pathological mutations in EP300c.1519AG;p.S507G51.1% in CUX1(c.328GA;p.D110N), and 47.0% in FGFR3 c.1738GA;p.D580N Summary/Conclusion: In summary, this is the first report of Coexistence of β‐thalassemia and Essential Thrombocythaemia. Theacquired mutation of CUX1EP300 and FGFR3 plays a potential role in disease progression and transformation. ∗∗Correspondence to: Dr Jian Huang, E‐mail: househuang@zju.edu.cn Acknowledgment The research was supportedby funding of the Science and Technology Department of Zhejiang Province, China(2016C33160), and Yiwu public technologyresearch projects, Zhejiang Province, China (2016‐S‐05)., the key medical discipline of YiwuChinaHematology2018‐2020.