MUTATION IVS-II-848 (C->A); 
       105         105
CAACAG^CTC->CAAAAG^CTC
AMINO ACID REPLACEMENT None
TYPE OF BETA-THAL beta+
MECHANISM This C->A change at position 848 next to the invariant AG dinucleotide, diminishes splicing but does not eliminate it
IDENTIFICATION Cloning and amplification of the beta-globin gene; DNA sequencing; dot-blot analysis with allele specific probes
HEMATOLOGY IN HETEROZYGOTE(S) Not given
HEMATOLOGY IN HOMOZYGOTE(S) None known
OCCURRENCE In an Iranian and a few Egyptian and Black families
HAPLOTYPE [+ - - - - - + + +]
FOUND IN COMBINATION WITH ABNORMAL HB(S) None
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) Found in combination with the -29 (A->G) mutation in a 48-year-old female: Hb 5.8 g/dl; MCV 97 fl; MCH 25.4 pg; Hb A2 4.0%; Hb F 74.0%; Hb A 23.0%
OTHER INFORMATION In vitro expression studies reveal a diminished formation of normal mRNA and the presence of an abnormal message using a cryptic IVS-II acceptor site at IVS-II-579
       
REFERENCES
1. Wong, C., Antonarakis, S.E., Goff, S.C., Orkin, S.H., Forget, B.G., Nathan, D.G., Giardina, P.J.V., and Kazazian, H.H., Jr.: Blood, 73:914, 1989.
2. Gonzalez-Redondo, J.M., Stoming, T.A., Lanclos, K.D., Gu, Y.C., Kutlar, A., Kutlar, F., Nakatsuji, T., Deng, B., Han, I.S., McKie, V.C., and Huisman, T.H.J.: Blood, 72:1007, 1988.

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.