MUTATION Codons 31/32 (+CGG) 
  30  31  32    30      31  32
AG^G·CTG·CTG->AG^G·CGG·CTG·CTG
AMINO ACID REPLACEMENT +Arg between positions 30/31: 
 30      31  32
ARG·ARG·Leu-Leu
TYPE OF BETA-THAL beta° (dominant beta°-thal)
MECHANISM The abnormal mRNA translates into an abnormal beta chain which is 147 amino acids long and is unstable; an abnormal Hb was not recovered
IDENTIFICATION Amplification of the beta-globin gene; DNA sequencing; dot-blot analysis with allele specific probes; ASO
HEMATOLOGY IN HETEROZYGOTE(S) Proband: Hb 9.9 g/dl; MCV 79.8 fl; MCH 23.5 pg; reticulocytes 9.9%; Hb A2 4.9%; Hb F 1.9%; splenomegaly (two carriers are splenectomized); dark-colored urine; icteric
HEMATOLOGY IN HOMOZYGOTE(S) Not observed
OCCURRENCE Found in a Spanish family (four members)
HAPLOTYPE Not done
FOUND IN COMBINATION WITH ABNORMAL HB(S) Not reported
FOUND IN COMBINATION WITH BETA-THAL ALLELE(S) Not reported
OTHER INFORMATION The three base pair insertion was confirmed by electrophoretic examination of cDNA fragments
       
REFERENCES
1. Negri Arjona, S, Maldonado Eloy-Garcia, J., Gu, L-H., Smetanina, N.S., and Huisman, T.H.J.: Br. J. Haematol., 93:841, 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.