MUTATION Codon 32 (T->A) CTG->CAG; codon 98 (G->A) GTG->ATG
 
AMINO ACID REPLACEMENT Position 32 Leu->Gln (Hb Medicine Lake); position 98 Val->Met
TYPE OF BETA-THAL beta°
MECHANISM Dominant beta-thal due to hyperunstable variant
IDENTIFICATION Amplification of the beta-globin gene; sequencing of DNA
HEMATOLOGY IN HETEROZYGOTE(S) Found in a 2-year-old Caucasian girl; parents are normal; hematology at 19 months: Hb 7.8 g/dl; MCV 73 fl; reticulocytes 19.5%; Hb F 6.8%; Hb A2 3.4%
HEMATOLOGY IN HOMOZYGOTE(S) None observed
OCCURRENCE In one carrier
HAPLOTYPE Not determined
FOUND IN COMBINATION WITH ABNORMAL HB(S) None found
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) None found
OTHER INFORMATION The variant is the same as the unstable Hb Köln but with an additional beta32(B14)Leu->Gln substitution; the variant could not be isolated; the betaX-mRNA is stable; no abnormally spliced mRNA detected
       
REFERENCES
1. Coleman, M.B., Lu, Z-H., Smith, C.M., II, Adams, J.G., III, Harrell, A., Plonczynski, M., and Steinberg, M.H.: J. Clin. Invest., 95:503, 1995.


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.