Hb S-Oman beta6(A3)Glu->Val;
beta121(GH4)Glu->Lys
         
HEMATOLOGY Presumably normal; the carrier had microcytosis and hypochromia due to a coexisting alpha-thal-2 homozygosity
ELECTROPHORESIS Hb X moves slower than Hb C at alkaline pH
CHROMATOGRAPHY Hb X can be separated from Hb A and Hb A2 by anion exchange HPLC
STRUCTURE STUDIES Tryptic digestion of Hb X; separation of peptides by fingerprinting; amino acid analysis
DNA ANALYSES Not reported; presumed mutation GAG->GTG and GAA->AAA at codons 6 and 121
FUNCTION STUDIES Sickling test is positive
STABILITY The same as that of Hb S
OCCURRENCE Found in a 24-year-old male from Oman
OTHER INFORMATION Hb X was 14.5% of total Hb; Hb X is considerably less soluble than Hb S; comparable to Hb S-Antilles; the beta121 Glu-> Lys replacement is characteristic for Hb O-Arab
       
REFERENCES
1. Langdown, J.V., Williamson, D., Knight, C.B., Rubenstein, D., and Carrell, R.W.: Br. J. Haematol., 71:443, 1989.


This material is from the book A Syllabus of Human Hemoglobin Variants (1996) by Titus H.J. Huisman, Marianne F.H. Carver, and Georgi D. Efremov, published by The Sickle Cell Anemia Foundation in Augusta, GA, USA. Copyright © 1996 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 written permission.