The Interaction of a-Thalassaemia and Haemoglobin

SUMMARY. An American Negro woman was found to have HbH disease in association with HbG Philadelphia (a68-asn+lys). Starch gel electrophoresis failed to reveal the presence of any HbA or HbA, and studies of globin chain synthesis indicated absence of aA production. The aG/p synthesis ratio was 0.63. The woman’s son and her two half-sibs had a-thalassaemia trait with no HbH and a/P synthesis ratios of 0.84,0.84 and 0.76. The data indicate that there is no functioning aA gene linked to the aG gene. The absence of a* synthesis by the propositus also indicates that the a-thalassaemia gene trans to the aG gene completely suppresses a chain production, the first evidence for such a gene in Negroes.