Polycythaemia associated with homozygosity for the abnormal haemoglobin Sherwood Forest (beta 104 (G6)Arg-->Thr).
We describe a 22-year-old Pakistani male with polycythaemia associated with homozygosity for a high-affinity haemoglobin mutant, Hb Sherwood Forest. This haemoglobin variant has an amino acid substitution in the beta globin chain at position 104, Arg-->Thr. In the two previously reported instances of this haemoglobin mutant the individuals were heterozygotes and were haematologically normal. We show here that the homozygous state for the mutation is associated with a compensatory erythrocytosis resulting from decreased delivery of oxygen to the tissues. A family study showed that both parents and two siblings are heterozygotes for the haemoglobin mutant and are haematologically normal. To our knowledge, this represents the first example of a beta-globin mutation producing polycythaemia in homozygotes but not in heterozygotes.
Williamson
D
D
Department of Haematology, University of Cambridge.
Beresford
C H
CH
Langdown
J V
JV
Anderson
C C
CC
Green
A R
AR
D000328:Adult; D001483:Base Sequence; D004247:DNA / Q000737:chemistry; D004588:Electrophoresis, Cellulose Acetate; D005914:Globins / Q000235:genetics; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010100:Oxygen / Q000097:blood; D011086:Polycythemia / Q000097:blood / Q000235:genetics*
D006455:Hemoglobins, Abnormal; C079325:hemoglobin Sherwood Forest; D005914:Globins; D004247:DNA; D010100:Oxygen