MUTATION		- -(MED-I); deletion of ~17.5 kb including both alpha-globin genes (see Fig. 24 for location)
AMINO ACID REPLACEMENT		None
TYPE OF ALPHA-THAL		alpha-Thal-1 [- -/]
MECHANISM		The absence of both alpha-globin genes prevents the formation of alpha-mRNA
IDENTIFICATION		Gene mapping; PCR methodology
HEMATOLOGY IN HETEROZYGOTE(S)		Hb 11-14 g/dl; MCV 60-70 fl; MCH 20-25 pg; Hb A2 2.0-2.2%; alpha/beta ratio ~0.6-0.7
HEMATOLOGY IN HOMOZYGOTE(S)		Hydrops fetalis
OCCURRENCE		In Mediterranean populations
HAPLOTYPE		Not determined
FOUND IN COMBINATION		With Hb S; Hb C
FOUND IN COMBINATION		Mainly with the -alpha(3.7 kb) deletion or nondeletional alpha-thal causing Hb H disease; Hb 9-10 g/dl; MCV 60-68 fl; MCH 20-22 pg; Hb H variable; often Hb Bart's; alpha/beta ratio ~0.4
OTHER INFORMATION		None

REFERENCES
1.		Pressley, L., Higgs, D.R., Clegg, J.B., and Weatherall, D.J.: Proc. Natl. Acad. Sci. USA, 77:3586, 1980.
2.		Sonati, M.F., Kimura, E.M., Grotto, H.Z.W., Tavella, M.H., and Costa, F.F.: Acta Haematol., 87:145, 1992.
3.		Bowden, D.K., Vickers, M.A., and Higgs, D.R.: Br. J. Haematol., 81:104, 1992.
4.		Baysal, E., Kleanthous, M., Bozkurt, G., Kyrri, A., Kalogirou, E., Angastiniotis, M., Ioannou, P., and Huisman, T.H.J.: Br. J. Haematol., 89:496, 1995.

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This material is from the book A Syllabus of Thalassemia Mutations (1997) by Titus H.J. Huisman, Marianne F.H. Carver, and Erol Baysal, published by The Sickle Cell Anemia Foundation in Augusta, GA, USA. Copyright © 1997 by Titus H.J. Huisman. All rights reserved. Neither this work nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, microfilming and recording, or by any information storage and retrieval systems, without permission in writing from the Author.