A Case of Myosin Heavy Chain 9-Related Disorder Following Splenectomy Due to Misdiagnosis of Idiopathic Thrombocytopenic Purpura

This case study reports a patient with Myosin Heavy Chain 9 (MYH9)-related disorder (MYH9-RD) which is characterized by congenital macrothrombocytopenia, Dohle-like bodies, sensorineural hearing loss, cataracts, and glomerulopathy. Often misdiagnosed as idiopathic thrombocytopenic purpura (ITP), MYH9RD requires accurate identification to avoid inappropriate treatments like steroids, rituximab, or splenectomy. Platelet transfusions were traditionally the only therapeutic option, but thrombopoietin receptor agonists (TPO-RA), specifically eltrombopag, have shown success in MYH9-RD treatment. The case report involves a 27 -year -old male with chronic ITP post-splenectomy, revealing thrombocytopenia, mild anemia, giant platelets, kidney failure, and hearing loss. Genetic testing identified a c.287C>T; p.(Ser96Leu) variant associated with MYH9-RD. Eltrombopag treatment, initiated before the definitive diagnosis, exhibited clinical and laboratory success. The study discusses the evolving landscape of treatments for inherited thrombocytopenias, emphasizing eltrombopag's efficacy, especially postsplenectomy, and its potential application in short-term preparations for elective surgeries. The study underscores the importance of timely MYH9-RD diagnosis, preventing misdiagnoses and inappropriate treatments. Eltrombopag stands out as a potential therapeutic option, offering effective platelet count management, especially post-splenectomy, with ongoing research exploring alternative TPORAs. As MYH9-RDs are rare, increased awareness among healthcare professionals is crucial to ensure accurate diagnoses and optimal patient care.