MYH9-related diseases in the differential diagnosis of chronic immune thrombocytopenic purpura

Year 2024, , 256 - 258, 31.05.2024

Simge Horoz Bicer Mehmet Fatih Orhan

https://doi.org/10.5472/marumj.1487461

Abstract

Myosin heavy chain 9 (MYH9)-related platelet disorders (MYH9-RD) belong to the group of inherited thrombocytopenias
characterized by giant platelets and Döhle bodies. The process leading to the diagnosis of MYH9-RD in a 13-year-old male patient,
followed by the diagnosis of chronic immune thrombocytopenic purpura (ITP), is described. The patient had thrombocytopenia
with increased mean platelet volume since he was a little boy. Low CD41, CD42 and CD61 levels were detected in blood tests sent to
complete missing diagnostic tests. Platelet aggregation tests were also abnormal. The requested genetic test revealed a heterozygous
mutation in the MYH9 gene. The patient’s audiogram and kidney functions were normal. In conclusion, because MYH9-RD appears
to be rare, it is of great importance to maintain a high index of suspicion when managing patients diagnosed with chronic ITP.
Additional complaints and findings should be considered at every outpatient clinic examination to make a more accurate diagnosis
and prevent unnecessary treatments.

Keywords

Thrombocytopenia, Chronic ITP, MYH9, Mean Platelet Volume, Children

References

• Althaus K, Greinacher A. MYH9-related platelet disorders. Semin Thromb Hemost 2009;35:189-203. doi:10.1055/S-0029.122.0327/ID/21/BIB
• Marques MI, Carrington Queiró L, Prior AR, Lopo Tuna M. MYH9-related disorders: a rare cause of neonatal thrombocytopaenia. BMJ Case Rep 2018;2018. doi:10.1136/ BCR-2018-224510
• Tabibzadeh N, Fleury D, Labatut D, et al. MYH9-related disorders display heterogeneous kidney involvement and outcome. Clin Kidney J 2018;12:494-502. doi:10.1093/CKJ/ SFY117
• Kelley MJ, Jawien W, Ortel TL, Korczak JF. Mutation of MYH9, encoding non-muscle myosin heavy chain A, in May-Hegglin anomaly. Nat Genet 2000;26:106-8. doi:10.1038/79069
• Favier R, Raslova H, Kremlin-Bic L, Roussy G. Progress in understanding the diagnosis and molecular genetics of macrothrombocytopenias. Br J Haematol 2015;170:626-39. doi:10.1111/BJH.13478
• Estcourt LJ, Malouf R, Doree C, Trivella M, Hopewell S, Birchall J. Prophylactic platelet transfusions prior to surgery for people with a low platelet count. Cochrane Database Syst Rev 2018;2018:CD012779. .doi:10.1002/14651858.CD012779. PUB2
• Economou M, Batzios SP, Pecci A, et al. MYH9-Related Disease. J Pediatr Hematol Oncol 2021;34:412-5. doi:10.1097/ mph.0b013e318257a64b
• Fernandez-Prado R, Carriazo-Julio SM, Torra R, Ortiz A, Perez-Gomez MV. MYH9-related disease: it does exist, may be more frequent than you think and requires specific therapy. Clin Kidney J 2019;12:488-93. doi:10.1093/CKJ/SFZ103
• Gokcay Bek S, Eren N, Ergul M. Difficult diagnosis of myosin heavy chain 9 related platelet disorder. Kocaeli Medical Journal 2020;9:120-3. doi:10.5505/KTD.2020.33602
• Orphanet. MYH9 related disease MYH9 related disorder.. https://www.orpha.net/consor/cgi-bin/Disease_Search. php?lng=EN&data_id=18198&Disease_Disease_Search_ diseaseGroup=MYH9relateddisease&Disease_Disease_ Search_diseaseType=Pat&Disease(s)/group%20of%20 diseases=MYH9-related-disease—MYH9-related-disorder- &title=MYH9-related-disease—MYH9-related-disorder- &search=Disease_Search_Simple Accessed July 30, 2023.
• Verver E, Pecci A, De Rocco D, et al. R705H mutation of MYH9 is associated with MYH9-related disease and not only with non-syndromic deafness DFNA17. Clin Genet 2015;88:85-9. doi:10.1111/CGE.12438
• Economou M, Batzios SP, Pecci A, et al. MYH9-related disease. J Pediatr Hematol Oncol 2021;34:412-5. doi:10.1097/ mph.0b013e318257a64b