Hb F-Charlotte, Hb F-Sassari, Hb F-Waynesboro
IDENTIFICATION These variants were discovered by reversed phase HPLC; no separation by electrophoretic or chromatographic procedures. The gammaX chain of each carrier eluted at the same position on a reversed phase column. The differences are the presence of an additional AgammaT variant in the babies with Hb F-Sassari and Hb F-Waynesboro.
Quantities of the chains:   Ggamma   gammaX   Agamma   AgammaT  

Hb F-Charlotte baby 72.5 9.7 17.8 0
Hb F-Sassari baby 37.1 32.4 19.3 11.2
Hb F-Waynesboro baby 43.0 29.2 14.4 13.3
DNA ANALYSES Extensive DNA sequencing analysis has shown the following: The three babies have a normal chromosome with a normal Ggamma gene and a normal Agamma gene. The Ggamma gene of the second chromosome of the Hb F-Charlotte baby is also normal, but that of the Hb F-Waynesboro baby is mutated at codon 75 (GgammaX with ATA->ACA or Ile->Thr). Thus, the total Ggamma level in the Hb F from the Hb F-Charlotte baby is normal at 72.5%, and that in the Hb F-Waynesboro baby is also normal [Ggamma (43.0%) + gammaX (29.2%) = 72.2%]. The sequences of the Agamma genes in both babies suggest a limited gene conversion by replacing a segment of the Agamma gene by that of a Ggamma gene, which makes the 3' end of the gene different from that of a normal Agamma gene. Both hybrid genes have an ATA->ACA mutation at codon 75 (Ile->Thr), while that in the Hb F-Charlotte baby has an additional GCA->GGA mutation at codon 136. The products of these hybrid genes will occupy different positions in the chromatogram.
Hb F-Charlotte: gammaX = AgammaX = Agamma (75 Ile->Thr; 136 Ala->Gly)
Hb F-Waynesboro: gammaX = GgammaX = Ggamma (75 Ile->Thr)
1. Plaseska, D., Kutlar, F., Wilson, J.B., Fei, Y.J., and Huisman, T.H.J.: Hemoglobin, 14:617, 1980.
2. Ferranti, P., Barone, F., Pucci, P., Malorni, A., Marino, G., Pilo, G., Manca, L., and Masala, B.: Hemoglobin, 18:307, 1994.
3. Gu, L-H., Öner, C., and Huisman, T.H.J.: Hemoglobin, 19:413, 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.