MUTATION +1480 (C->G); also known as 3' terminating codon +6 (C->G)
146 147  1    6    
CAC TAA GCTCGCTTTC
His Term |
G
AMINO ACID REPLACEMENT None
TYPE OF BETA-THAL beta+ (silent; only expressed in compound heterozygotes)
MECHANISM Not clear; perhaps decreased stability of mRNA
IDENTIFICATION Amplification of the beta-globin gene; DNA sequencing; dot-blot analysis with allele specific probes
HEMATOLOGY IN HETEROZYGOTE(S) Four heterozygous relatives; beta/alpha in vitro chain ratio 0.8-0.84
Hb MCH MCV A2 F
AA 14.9 32.3 93.3 2.35 <1.0
A/+6 14.3 29.2 87.4 2.35 <1.0
HEMATOLOGY IN HOMOZYGOTE(S) None
OCCURRENCE In a Greek family
HAPLOTYPE VI [- - + + - - - +]
FOUND IN COMBINATION WITH ABNORMAL HB(S) None
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) The 9-year-old proband is a compound heterozygote for this mutation and IVS-I-1 (G->A); Hb 7.7 g/dl; Hb A2 4.7%; Hb F 10.0%; rarely requires blood transfusions; mild thalassemic features
OTHER INFORMATION None
       
REFERENCES
1. Jankovic, L., Dimovski, A.J., Kollia, P., Karageorga, M., Loukopoulos, D., and Huisman, T.H.J.: Int. J. Hematol., 54:289, 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.