TYPE Cantonese Ggamma(Agammadeltabeta)°-Thal (see Fig. 16)
CAUSE A large deletion that removes the Agamma, delta, and beta genes. It extends downstream for an unknown distance. The 5' end of the deletion is immediately 3' to the Agamma gene. The exact 3' breakpoint is not defined.
DETECTION Gene mapping with different enzymes and probes.
PHENOTYPE As in other types of (Agammadeltabeta)°-thal, the Cantonese type is characterized in heterozygotes by a mild anemia, microcytosis, and hypochromia. The hematological data for two heterozygotes are: Hb 10. 5 and 11.1 g/dl; RBC 3.5 and 4.4 x 1012/l; MCV 81 and 83 fl; Hb A2 3.0 and 2.5%; Hb FAD 19.1 and 19.6%; Ggamma 96.5 and 92.8%. No homozygotes were found.
DISTRIBUTION This deletion was observed in two members of a Cantonese family.
1. Zeng, Y-T., Huang, S-Z., Chen, B., Liang, Y-C., Chang, Z-M., Harano, T., and Huisman, T.H.J.: Blood, 66:1430, 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.