MUTATION		Codons 127/128 (-AGG); CAG·GCT(Gln·Ala)->C-- -CT(Pro)
AMINO ACID REPLACEMENT		See above (Hb Gunma)
TYPE OF BETA-THAL		beta°
MECHANISM		The abnormal beta chain (145 amino acids long; one extra Pro; minus Gln,Ala) is likely unstable and will be catabolized rapidly, causing a beta-thal condition
IDENTIFICATION		Cloning of the beta-globin gene; DNA sequencing; DNA amplification; sequencing
HEMATOLOGY IN HETEROZYGOTE(S)		Mild anemia; decreased MCV (~65 fl); decreased MCH (~20 pg); Hb F and Hb A2 elevated; no inclusion bodies after incubation with dye; beta/alpha in vitro synthetic ratio 0.45
HEMATOLOGY IN HOMOZYGOTE(S)		None
OCCURRENCE		In 42 members of 11 Japanese families
HAPLOTYPE		VII [+ O - - - - - +]
FOUND IN COMBINATION WITH ABNORMAL HB(S)		None
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S)		None
OTHER INFORMATION		No abnormal beta chain could be isolated; it is unclear why this anomaly does not express itself as a dominant TYPE OF BETA-THAL

REFERENCES
1.		Fucharoen, S., Fucharoen, G., Fukumaki, Y., Nakayama, Y., Hattori, Y., Yamamoto, Ki., and Ohba, Y.: Blood, 76:1894, 1990.
2.		Hattori, Y., Yamane, A., Yamashiro, Y., Matsuno, Y., Yamamoto, Ki., Yamamoto, Ku., Ohba, Y., and Miyaji, T.: Hemoglobin, 13:657, 1989.
3.		Ohba, Y., Hattori, Y., Harano, T., Harano, K., Fukumaki, Y., Ideguchi, H., Cho, H.I., and Park, S.S.: Hemoglobin, 21:191, 1997.

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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.