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

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.