TYPE English (epsilongammadeltabeta)°-Thal (see Fig. 17)
CAUSE A large deletion of ~100 kb that spans the region from exon 3 of the Ggamma gene to upstream of the LCR. The deletion includes the epsilon and part of the Ggamma genes but not the Agamma, delta, and beta genes. The beta gene remains intact but inactive.
DETECTION Gene mapping with different enzymes and probes.
PHENOTYPE Heterozygosity results in a beta-thal trait-like phenotype but with normal Hb A2 values. The clinical course is marked by neonatal hemolytic anemia, followed by the typical hematological features of beta-thal minor. Hematological data for two patients were: Hb 11.0 and 11.3 g/dl; MCV 58 and 56 fl; MCH 18.3 and 19.0 pg; Hb F 0.8 and 2.7%; Hb A2 2.8 and 2.9%; alpha/beta ratio 2.0 and 2.7, respectively. The Ggamma:Agamma ratio showed excess Agamma-globin chains.
DISTRIBUTION Detected in an English family.
1. Curtin, P., Pirastu, M., Kan, Y.W., Gobert-Jones, J.A., Stephens, A.D., and Lehmann, H.: J. Clin. Invest., 76:1554, 1985.

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.