MYH9-Related Platelet Disorders
Myosin heavy chain 9 (MYH9)-related platelet disorders incorporate a group of four, inherited thrombocytopenic syndromes, May-Hegglin anomaly (MHA), Epstein syndrome (EPS), Fechtner syndrome (FTS), and Sebastian platelet syndrome (SPS).
The syndromes are characterized by giant platelets, thrombocytopenia, and variable bleeding symptoms. There is a wide variability in presenting symptoms, and although platelet function is generally normal, severe bleeding is sometimes observed.
Due to the infrequency of the disease, it is difficult to evaluate the maternal and fetal risk. However, prior reports suggest that delivery and pregnancy are not associated with significant hemorrhaging in parturients with MYH9.
Early diagnosis of MYH9 is essential for optimal postpartum outcomes. Therefore, MYH9 should be suspected in patients with low platelet counts, especially in cases with genetic history of thrombocytopenia, mean platelet volume larger than 12 fl, and thrombocytopenia which is unresponsive to corticosteroids.
Clinical management of these parturients is complex and requires a multidisciplinary approach. In parturients with prior bleeding, hemostatic coverage should be initiated for mild hemorrhage treatment and platelet transfusions for severe bleeding.
While it remains unclear which mode of delivery will provide optimal postpartum outcomes, care should be taken to reduce the risk of bleeding and perineal trauma.
Anesthetic management of these parturients should include a full peripartum anesthetic evaluation of clinical bleeding, and manual platelet count should be performed for these parturients.
KeywordsMay-Hegglin anomaly Epstein syndrome Fechtner syndrome Sebastian platelet syndrome and pregnancy
- 3.Seri M, Pecci A, Di Bari F, Cusano R, Savino M, Panza E, et al. MYH9-related disease: May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome, and Epstein syndrome are not distinct entities but represent a variable expression of a single illness. Medicine (Baltimore). 2003;82(3):203–15.Google Scholar
- 6.Toothaker LE, Gonzalez DA, Tung N, Lemons RS, Le Beau MM, Arnaout MA, et al. Cellular myosin heavy chain in human leukocytes: isolation of 5′ cDNA clones, characterization of the protein, chromosomal localization, and upregulation during myeloid differentiation. Blood. 1991;78(7):1826–33.PubMedGoogle Scholar
- 8.Heath KE, Campos-Barros A, Toren A, Rozenfeld-Granot G, Carlsson LE, Savige J, et al. Nonmuscle myosin heavy chain IIA mutations define a spectrum of autosomal dominant macrothrombocytopenias: May-Hegglin anomaly and Fechtner, Sebastian, Epstein, and Alport-like syndromes. Am J Hum Genet. 2001;69(5):1033–45.CrossRefGoogle Scholar