MUTATION - -(YEM); a deletion of +39 kb involving the two alpha genes (Fig. 24)
 
AMINO ACID REPLACEMENT None
TYPE OF ALPHA-THAL alpha-Thal-1 [- -/]
MECHANISM This large deletion removes both alpha-globin genes but not the zeta-globin gene; no functional alpha-mRNAs is produced
IDENTIFICATION Gene mapping; see scheme below
Restriction maps of the normal alpha-globin gene cluster and the location of the Yemenite deletion. The sizes of abnormal zeta-specific fragments are given in parentheses at left. The solid bar at the bottom shows the location of the deletion and the open bars indicate the limits of the breakpoints (from Ref. 1).[Figure not yet available on-line.]
HEMATOLOGY IN HETEROZYGOTE(S) Hb 10.2 g/dl; MCV 71 fl; MCH 20.8 pg; alpha/beta ratio 0.66 (mother of one of the patients with Hb H disease)
HEMATOLOGY IN HOMOZYGOTE(S) None
OCCURRENCE Found in a few Yemenite families living in Israel
HAPLOTYPE Not determined
FOUND IN COMBINATION WITH ABNORMAL HB(S) Not reported
FOUND IN COMBINATION With the -alpha(3.7 kb) deletion and with a nondeletional alpha-thal causing Hb H disease: Hb 9.6-10.9 g/dl; MCV 62-68 fl; MCH 17-20 pg; alpha/beta ratio 0.16, 0.24, 0.29, 0.36
OTHER INFORMATION None
       
REFERENCES
1. Shalmon, L., Kirschmann, C., and Zaizov, R.: Am. J. Hematol., 45:201, 1994.


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.