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Studies on the Proportion and Synthesis of Haemoglobin G Philadelphia in Red Cells of Heterozygotes, a Homozygote, and a Heterozygote for both Haemoglobin G and α Thalassaemia
Author(s) -
Milner P. F.,
Huisman T. H. J.
Publication year - 1976
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1976.tb00191.x
Subject(s) - microcytosis , heterozygote advantage , biology , genetics , microbiology and biotechnology , compound heterozygosity , allele , medicine , gene , iron deficiency , anemia
SUMMARY. The proportion of Hb G Philadelphia (α68‐Asnalys) in heterozygotes has been found to have a well‐defined bimodal distribution around means of 33% and 46% Hb G. Microcytosis and hypochromia are consistently associated with the latter group, who also have a decreased ratio of α/β‐chain synthesis in the peripheral blood, but these characters are not linked to the Hb‐Gα gene, because a parent with microcytosis and 46% Hb Gα may have offspring with 33% Hb G without significant microcytosis. In one family a subject with Hb G and Hb G 2 but no Hb A or Hb A 2 is presumably a homozygote for α G . This subject has microcytosis and a decreased ratio of α/β chain synthesis. In another family a subject with Hbs H, G and G 2 but without Hbs A or A 2 is heterozygous for both Hb G and α thalassaemia 1. These findings are compatible with the hypothesis that the α G mutation occurs on a chromosome with only a single αchain locus and that the expression in heterozygotes as 46% or 33% Hb G is determined by the homologous chromosome in trans having either one or two normal α A genes respectively. The significance of this polymorphism for chromosomes carrying αchain genes is discussed.