TYPE Turkish (deltabeta)°-Thal (see Fig. 14)
CAUSE This condition is characterized by a ~30 kb deletion which includes the delta and beta genes. The 5' breakpoint is about 1.5 kb 5' to the enhancer-like sequence of Agamma, and the 3' breakpoint is located in the L1 repeat sequence 3' to the beta gene. The deletion is similar to that of the Indian type of (deltabeta)°-thal with a comparable 5' breakpoint but a 3' breakpoint which is 2-5 kb shorter.
DETECTION Restriction enzyme digestion with numerous enzymes and hybridization with different probes.
PHENOTYPE Mild anemia in the heterozygote (Hb 9-11 g/dl; PCV 0.27-0.33 l/l) with distinct microcytosis (MVC 63-66 fl) and hypochromia (MCH 20-22 pg), normal Hb A2 values (2.0; 2.9%) and increased Hb F levels (6.0; 15.0%). The level of Ggamma was not determined.
DISTRIBUTION Found in a 64-year-old Turkish male and his father.
1. Öner, R., Öner, C., Erdem, G., Balkan, H., Özdag, H., Erkan, M., Gümrük, F., Gürgey, A., and Altay, Ç.: Acta Haematol., 96:232, 1996.

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.