DIFFERENCES BETWEEN ALPHA- AND BETA-CHAIN MUTANTS OF HUMAN HAEMOGLOBIN AND BETWEEN ALPHA- AND BETA-THALASSAEMIA . POSSIBLE DUPLICATION OF ALPHA-CHAIN GENE

Human adult haemoglobin consists of two unlike pairs of polypeptide chains, and can be described as α2β2 Amino-acid substitutions in either of the two types of chain result in α- and β-chain variants. In thalassaemia, which causes a levered production of haemoglobin, the α or the β chain can be affected, the result being α- or β-thalassaemia. There is a quantitative difference in the proportion of α- and β-chain variants to normal haemoglobin in the respective heterozygotes, and there is also a difference in the pattern of inheritance of α- and β-thalassaemia: these could possibly be explained by assuming that man has one gene for the β- and two for the α-chain. © 1968, British Medical Journal Publishing Group. All rights reserved.