Hb Seal Rock alpha142, Term->Glu (TAA->GAA in alpha2);
modified C-terminal sequence is the same as
as Hb CS except that residue 142 is GLU
HEMATOLOGY Mild anemia with microcytosis and hypochromia in the heterozygote
ELECTROPHORESIS Hb X moves as two bands, slower than Hb A2 at alkaline pH
CHROMATOGRAPHY Hb X can be isolated by anion exchange chromatography; various alpha chain zones are obtained when Hb X is analyzed by reversed phase HPLC
STRUCTURE STUDIES Tryptic digestion of alphaX chain; separation of peptides by reversed phase HPLC; amino acid analysis; sequencing
DNA ANALYSES A TAA->GAA mutation at codon alpha142 (alpha2); the Hb Seal Rock abnormality can best be detected by sequencing of the alpha gene or by dot-blot analysis with specific probes
FUNCTION STUDIES Increased oxygen affinity
STABILITY Not reported
OCCURRENCE Found in a few Black families
OTHER INFORMATION When present in association with an alpha-thal-2 allele (3.7 kb deletion) a mild Hb H disease is observed
1. Bradley, T.B., Wohl, R.C., and Smith, E.J.: Clin. Res., 23:131A, 1975.
2. Fairbanks, V., Merritt, D., Rodgers, D., Thibodeau, S., Steinberg, M., Coleman, M., and Jones, R.: Blood, 86:657a (Suppl. 1), 1995.

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.