MUTATION		-202 (C->G) Ggamma; nd-HPFH
IDENTIFICATION		Cloning; DNA sequencing
HEMATOLOGY IN HETEROZYGOTE(S)		Normal; Hb F 16.7 (14.0-21.0)% (n=5) Ggamma nearly 100% (determined with the chemical gamma-CB3 procedure); Hb A2 1.75 (1.3-2.2)% (n=5)
HEMATOLOGY IN HOMOZYGOTE(S)		Not observed
OCCURRENCE		In a few Black families
HAPLOTYPE		Not determined
FOUND IN COMBINATION WITH ABNORMAL HB(S)		With Hb S: normal hematology; Hb F 20.1 (18.0-23.5)% (n=4); Hb A2 2.3 (2.1-2.6)% (n=4); Hb A 30.0 (24.0-36)% (n=4)
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S)		Not observed
MECHANISM		This mutation in a binding site of the ubiquitous proteins SpI and GTi increases the Sp-I binding which may cause an overexpression of the Ggamma-globin gene; another possibility: destabilization of an intramolecular triplex present in this section of the 5' flanking region

REFERENCES
1.		Collins, F.S., Stoeckert, C.J., Jr., Serjeant, G.R., Forget, B.G., and Weissman, S.M.: Proc. Natl. Acad. Sci. USA, 81:4894, 1984.
2.		Huisman, T.H.J., Miller, A., and Schroeder, W.A.: Am. J. Hum. Genet., 27:765, 1975.

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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.