MUTATION IVS-I-117 (G->A) alpha1 gene; 
      32   
CAG^G·ATG->
CAA^G·ATG
AMINO ACID REPLACEMENT None
TYPE OF ALPHA-THAL alpha-Thal-2 [alphaalpha(T)/alphaalpha]
MECHANISM This G->A replacement occurs in the acceptor splicing site which interferes with the correct splicing of the RNA
IDENTIFICATION Amplification; sequencing; dot-blot analysis with allele specific probes; ASO
HEMATOLOGY IN HETEROZYGOTE(S) Not observed
HEMATOLOGY IN HOMOZYGOTE(S) The only homozygote was also compound heterozygous for Hb S and a beta+-thal
OCCURRENCE Found in several Indian families
HAPLOTYPE Not determined
FOUND IN COMBINATION With Hb S and beta-thal; see figure below for the effect on the quantities of Hb S in alpha-thal carriers.
The levels of Hb S in 78 adult Indian Hb S heterozygotes. The data are also plotted according to the types of alpha-thal-2. The four black dots (one in group 3 and three in group 4) are AS subjects with an additional Hb Koya Dora (KD) mutation (alpha2, codon 142, TAA->TCA); these values are replotted as a separate group at right. The values marked with arrows are from subjects with the IVS-I-117 (G->A) mutation (from Ref. 1).[Figure not yet available on-line.]
OTHER INFORMATION None
       
REFERENCES
1. Çürük, M.A., Baysal, E., Gupta, R.B., Sharma, S., and Huisman, T.H.J.: Br. J. Haematol., 85:148, 1993.

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.