Clinical Pathology: Hematology & Coagulation

• Congenital macrothrombocytopenia syndromes include May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome, Epstein syndrome, Bernard-Soulier (BS) syndrome, gray platelet syndrome, and X-linked macrothrombocytopenia with dyserythropoiesis.

• May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome, and Epstein syndrome are MYH9-related diseases that are characterized by mutations in the myosin heavy chain 9 (MYH9) gene.

• MYH9-related disorders all have giant platelets (i.e., platelets at least the size of red blood cells [RBCs]) and are distinguished by the presence or absence of Döhle-like inclusions, hearing loss, nephritis, and cataracts.

• The majority of the MYH9 mutations show autosomal dominant inheritance.

• Most patients with MYH9-related disorders do not have clinically significant bleeding problems.

Bolton-Maggs PH, Chalmers EA, Collins PW, et al: A review of inherited platelet disorders with guidelines for their management on behalf of the UKHCDO. Br J Haematol 2006;135:603–633.

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