MUTATION Codons 123/124/125 (-ACCCCACC); ACC·CCA·CCA(Thr·Pro·Pro)->--- --- --A
 
AMINO ACID REPLACEMENT Shortened betaX chain (beta-Khon Kaen)
TYPE OF BETA-THAL Dominant inclusion body beta-thal trait
MECHANISM This deletion changes the reading frame and results in the synthesis of a betaX chain of 135 amino acids; the new codon 136 is a stop codon (TAA); the chain is likely rapidly catabolized creating this TYPE OF BETA-THAL
IDENTIFICATION Amplification of the beta-globin gene and cloning; DNA sequencing; HphI digestion
HEMATOLOGY IN HETEROZYGOTE(S) Not reported
HEMATOLOGY IN HOMOZYGOTE(S) Not observed
OCCURRENCE In a Thai patient with Hb E-beta-thal
HAPLOTYPE Not determined
FOUND IN COMBINATION WITH ABNORMAL HB(S) The proband is a 3-year-old boy with Hb E-beta-thal; he has severe disease: hepatosplenomegaly; Hb 2.7 g/dl; after splenectomy: Hb 8.2 g/dl; MCV 73.1 fl; MCH 25.6 pg; large inclusion bodies in blood upon incubation with dye
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) Not observed
OTHER INFORMATION Hb electrophoresis: Hb E (+A2) 40.0%; Hb F 60.0%; stability tests negative; the variant chain could not be detected by chromatographic procedures
       
REFERENCES
1. Fucharoen, G., Fucharoen, S., Jetsrisuparb, A., and Fukumaki, Y.: Blood, 78:537, 1991.


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.