MYH9-RD encompasses a series of autosomal dominant macrothrombocytopenias previously considered as distinct disorders, namely May-Hegglin anomaly (MHA; MIM#155100), Sebastian Syndrome (SBS; MIM#605249), Fechtner Syndrome (FTNS; MIM#153640), and Epstein Syndrome (EPTS; MIM#135650), all deriving from mutations in the MYH9 gene encoding for the heavy chain of nonmuscle myosin-IIA (NMMHC-IIA) [1]–[5]. This evidence concerns the gene MYH9 and autosomal dominant macrothrombocytopenia.