MUTATION		Codons 124/125/126 (+CCA); CCA·CCA·GTG(Pro·Pro·Val)->CCA·CCA·CCA·GTG(Pro·Pro·Pro·Val)
AMINO ACID REPLACEMENT		Extended beta chain (see above)
TYPE OF BETA-THAL		Dominant inclusion body beta-thal trait
MECHANISM		This extended betaX chain of 147 residues with its Pro-Pro-Pro sequence at the beginning of the H helix is unstable and rapidly catabolized causing this TYPE OF BETA-THAL
IDENTIFICATION		Amplification of the beta-globin gene; DNA sequencing
HEMATOLOGY IN HETEROZYGOTE(S)		Hb 7-9 g/dl; Hb A2 5.0%; Hb F <1.0%; hypochromia; target cells; basophilic stippling; splenomegaly
HEMATOLOGY IN HOMOZYGOTE(S)		None
OCCURRENCE		In a 1-year-old Armenian girl
HAPLOTYPE		Not determined
FOUND IN COMBINATION WITH ABNORMAL HB(S)		None
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S)		None
OTHER INFORMATION		The abnormal Hb or betaX chain could not be identified

REFERENCES
1.		Çürük, M.A., Molchanova, T.P., Postnikov, Yu.V., Pobedimskaya, D.D., Liang, R., Baysal, E., Kolodey, S., Smetanina, N.S., Tokarev, Yu.N., Rumyantsev, A.G., and Huisman, T.H.J.: Am. J. Hematol., 46: 329, 1994.

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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.