Hemoglobin Birmingham and hemoglobin Galicia: two unstable beta chain
variants characterized by small deletions and insertions
JB Wilson, BB Webber, H Hu, A Kutlar, F Kutlar, JF Codrington, JT Prchal, KM Hall, JM de Pablos and I Rodriguez
Department of Cell and Molecular Biology, Medical College of Georgia,
Augusta 30912-2100.
Two unstable hemoglobins (Hbs) causing rather severe hemolytic anemia have
been characterized. The beta chain of Hb Birmingham, found in an adult
black man, is characterized by the loss of -Leu-Ala-His-Lys- at positions
141, 142, 143, and 144 and their replacement by one Gln residue. These
changes are the result of a deletion of nine nucleotides, namely two base
pairs (bp) of codon 141, all of codons 142 and 143, and one bp of codon
144; the remaining CAG triplet (C from codon 141 and AG from codon 144)
codes for the inserted glutamine. In the beta chain of Hb Galicia from a
Spanish patient, His and Val at positions 97 and 98 are replaced by one Leu
residue. This is due to an ACG deletion in codons 97 and 98, which causes
the removal of one His and one Val residue, while the remaining CTG triplet
(C from codon 97 and TG from codon 98) codes for the inserted leucine
residue. Two mechanisms, namely slipped mispairing in the presence of short
repeats, and misreading by DNA polymerase due to a local distortion of the
DNA helix, are considered in explaining the origin of the small deletions.
Volume 75,
Issue 9,
pp. 1883-1887,
05/01/1990
Copyright © 1990 by The American Society of Hematology
