-.-(SEA),.deletion.of.~20.kb.including.b.html


MUTATION		- -(SEA); deletion of ~20 kb including both alpha-globin genes (see Fig. 24 for location)

AMINO ACID REPLACEMENT		None
TYPE OF ALPHA-THAL		alpha-Thal-1 [- -/]
MECHANISM		The deletion involves both alpha-globin genes and thus, no functional mRNA is formed
IDENTIFICATION		Gene mapping; PCR methodology
HEMATOLOGY IN HETEROZYGOTE(S)		Hb 11-13 g/dl; MCV 65-74 fl; MCH 18.0-19.5 pg; Hb A₂ 2.0-2.4%
HEMATOLOGY IN HOMOZYGOTE(S)		Hydrops fetalis
OCCURRENCE		In various East Asian populations
HAPLOTYPE		Not determined
FOUND IN COMBINATION		Mainly with Hb E [beta26(B8)Glu->Lys]
FOUND IN COMBINATION		With the -alpha(3.7), -alpha(4.2), -alpha(2.7), -alpha(3.5) alpha-thal-2 alleles; with nondeletional alpha-thal determinants; Hb Constant Spring; Hb Quong Sze causing Hb H disease
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.		Daenen, S., Reese, A.L., Kutlar, F., and Huisman, T.H.J.: Acta Haematol., 78:23, 1987.
3.		Bowden, V.A., Vickers, M.A., and Higgs, D.R.: Br. J. Haematol., 81:104, 1992.
4.		Waye, J.S. and Eng, B.: Hum. Hered., 44:61, 1994.

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.