MUTATION		Codon 22 (A->C); GAA(Glu)->GCA(Ala) (not listed in Table I; this mutation is likely not associated with thalassemia)
AMINO ACID REPLACEMENT		Glu->Ala
TYPE OF BETA-THAL		?
MECHANISM		Not clear
IDENTIFICATION		SSCP; amplification of the beta-globin gene; automated DNA sequencing
HEMATOLOGY IN HETEROZYGOTE(S)		Not presented
HEMATOLOGY IN HOMOZYGOTE(S)		Not reported
OCCURRENCE		Found in 15 Egyptians
HAPLOTYPE		Not reported
FOUND IN COMBINATION WITH ABNORMAL HB(S)		Not reported
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S)		Not reported
OTHER INFORMATION		This mutation is likely linked to a G->A polymorphism at codon 17 (AAG->AAA; Lys->Lys); no information is presented regarding the variant Hb with a Glu->Ala replacement which is Hb G-Coushatta [beta22(B4)]and is not associated with a beta-thal condition

REFERENCES
1.		El-Hashemite, N., Petrou, M., Khalifa, A.S., Heshmat, N.M., Rady, M.S., and Delhanty, J.D.A.: Hum. Genet., 99:271, 1997.

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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.