TYPE East European (deltabeta)°-Thal (see Fig. 14)
CAUSE Extensive gene mapping analysis has shown that the 5' breakpoint of the deletion occurs 1.7 kb 5' to the delta gene, leaving the two upstream Alu repeats intact. The region of the breakpoint is characterized by moderately high AT repeats. The 3' breakpoint occurs within the 5' end of the beta gene, between the StyI and HaeIII sites. The deletion removes 9.5 kb DNA.
DETECTION Gene mapping; no further details.
PHENOTYPE Eight heterozygotes from a large family are characterized with this deletion. The subjects have moderately decreased MCH (25-26 pg), slightly decreased MCV (74-79 fl), but a markedly increased Hb F (13-18%) with heterocellular distribution of Hb F in F-cells (67-86%), and a Ggamma:Agamma ratio of 73:27. Hb A2 levels were consistently low (1.7-2.1%) as expected.
DISTRIBUTION This abnormality has only been found in one Caucasian family of East European origin.
1. Palena, A., Blau, A., Stamatoyannopoulos, G., and Anagnou, N.P.: Blood, 79:6a (Suppl. 1), 1992.

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.