MUTATION		Codon 4 (ACT->ATT)
AMINO ACID REPLACEMENT		Thr->Ile
TYPE OF DELTA-THAL		delta+
MECHANISM		Unclear; maybe the abnormal Hb A2 is unstable
IDENTIFICATION		Amplification of the delta-globin gene; DNA sequencing; selective cleavage of PCR products
% HB A2 IN HETEROZYGOTE(S)		The Hb A2 level was 1.4-1.6% in three heterozygotes; 3.6% in a heterozygote who also carried a beta-thal gene
% HB A2 IN HOMOZYGOTE(S)		None
OCCURRENCE		Greek Cypriots
HAPLOTYPE		[- - - - + + + ± +]
FOUND IN COMBINATION WITH ABNORMAL HB(S)		None
FOUND IN COMBINATION WITH DELTA-THAL ALLELE(S)		None
OTHER INFORMATION		Additional changes: C->T at codon 97 (silent); AT deletion at position 722 of the IVS-II; C->T at -199 bp 5' to the Cap site

REFERENCES
1.		Trifillis, P., Kyrri, A., Kalogirou, E., Kokkofitou, A., Ioannou, P., Schwartz, E., and Surrey, S.: Blood, 82: 1647, 1993.

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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.