related platelet disorders belong to the group of inherited giant platelet disorders. The MYH-9
gene encodes the non-muscular myosin heavy chain IIA (NMMHCIIA), a cytoskeletal contractile protein. Several mutations in the MYH-9
gene lead to macrothrombocytopenia, and cytoplasmic inclusion bodies within leukocytes, while the number of megakaryocytes in the bone marrow is normal. Four overlapping syndromes, known as May-Hegglin anomaly, Epstein syndrome, Fechtner syndrome and Sebastian platelet syndrome, describe different clinical manifestations of MYH9
gene mutations. Macrothrombocytopenia is present in all affected individuals, whereas only some develop additional clinical manifestations such as renal failure, hearing loss and presenile cataracts. The bleeding tendency is usually moderate, with menorrhagia and easy bruising being most frequent. The biggest risk for the individual is inappropriate treatment due to misdiagnosis of chronic autoimmune thrombocytopenia. More than 30 mutations within the 40 exons of the MYH-9
gene leading to macrothrombocytopenia have been identified, of which the upstream mutations up to amino acid ∼1400 are more likely associated with syndromic manifestations than the downstream mutations. Diagnosis is based on identification of the granulocyte inclusion bodies using blood smears and immunofluorescence and is finally confirmed by identifying the mutation. Treatment is supportive and should be aimed to prevent iron deficiency anemia. Beside renal failure, the biggest risk for patients affected by a MYH-9
disorder are the adverse effects resulting form treatment based on the misdiagnosis of immune thrombocytopenia.
Prof. Dr. Andreas Greinacher, Institut für Immunologie und Transfusionsmedizin, Ernst-Moritz-Arndt-Universität Greifswald, Sauerbruchstraße, 17489 Greifswald, Germany, Tel. +49 3834 8654-82, Fax -89, firstname.lastname@example.org
Received: June 2, 2010
Accepted: August 19, 2010
Published online: September 15, 2010
Number of Print Pages : 8
Transfusion Medicine and Hemotherapy
Vol. 37, No. 5, Year 2010 (Cover Date: October 2010)
Journal Editor: Sibrowski W. (Münster)
ISSN: 1660-3796 (Print), eISSN: 1660-3818 (Online)
For additional information: http://www.karger.com/TMH
Copyright / Drug Dosage
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher or, in the case of photocopying, direct payment of a specified fee to the Copyright Clearance Center.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in goverment regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.