TYPE Black (deltabeta)°-Thal (see Fig. 14)
CAUSE A deletion that removes 12 kb of DNA extending from ~2.4 kb 5' to the delta gene to 200 bp at the 3' end of the beta gene. The inverted Alu I repeats 3' to the beta gene remain intact.
DETECTION Gene mapping with various enzymes and probes.
PHENOTYPE This deletion was reported in an American Black woman who was a compound heterozygote for this deletion and the betaS gene. She was asymptomatic with a mild anemia and 24.8% Hb F. Her husband and daughter had similarly high Hb F levels of 22.4 and 25.4%, respectively; however, the husband and daughter were found to be compound heterozygotes for the betaS gene and the Ghanaian type HPFH (HPFH-2). The patient's hematological data: Hb 11.4 g/dl; PCV 0.34 l/l; RBC 4.0 x 1012/l; MCV 85 fl; MCH 28.5 pg; MCHC 33.5 g/dl; Hb S 72.5%; Hb F 24.8%; Hb A2 2.7%; alpha/non-alpha biosynthetic ratio 1.07. Hb F distribution was pancellular; Ggamma levels in Hb F were not reported. No simple heterozygotes have been described.
DISTRIBUTION This rare deletion has only been found in one American Black woman.
1. Anagnou, N.P., Papayannopoulou, Th., Stamatoyannopoulos, G., and Nienhuis, A.W.: Blood, 65:1254, 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.