MUTATION T->C at codon 125 of the alpha2 gene; CTG->CCG
AMINO ACID REPLACEMENT Leu->Pro at position 125 (Hb Quong Sze)
TYPE OF ALPHA-THAL alpha-Thal-2 [alpha(T)alpha/alphaalpha]
MECHANISM Highly unstable Hb; as a result a decreased amount of alpha chain is produced
IDENTIFICATION Cloning or amplification of the alpha2-globin gene; DNA sequencing
HEMATOLOGY IN HETEROZYGOTE(S) No information available
HEMATOLOGY IN HOMOZYGOTE(S) Hb 9.8 g/dl; MCV 58 fl; MCH 19.5 pg; Hb A2 2.5%; no Hb H
OCCURRENCE Found at a low frequency in the population of (Southern) China
HAPLOTYPE Not determined
FOUND IN COMBINATION With alpha-thal-1 [- -/(SEA)] in three children [- -(SEA)/ alpha(QS)alpha]: Hb 6.0-8.5 g/dl; Hb F 0.3-1.4%; Hb H+Hb Bart's 10.9-26.5%
OTHER INFORMATION No protein was detected
1. Goossens, M., Lee, K.Y., Liebhaber, S.A., and Kan, Y.W.: Nature, 296:864, 1982.
2. Liang, S., Wen, X-J., and Lin, W-X.: Hemoglobin, 15:535, 1991.
3. Liang, R., Liang, S., Jiang, N.H., Wen, X-J., Zhao, J-B., Nechtman, J.F., Stoming, T.A., and Huisman, T.H.J.: Br. J. Haematol., 86:351, 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.