Interaction of alpha and beta thalassaemia genes in two Sardinian families.

Our paper describes two Sardinian families with alpha-beta thalassaemia interaction. In the first (family S), the propositus, whose haemoglobin pattern at birth consisted of about 25% Hb Bart's and 75% Hb F, successively developed a clinical and haematological picture typical of Cooleys anaemia. Haematological and globin chain synthesis studies together with these findings suggest that he is homozygous for beta 0 thalassaemia and heterozygous for alpha thalassaemia-1 and alpha thalassaemia-2. This conclusion is further substantiated by the finding of various combination of alpha and beta thalassaemia among his family members. In the P family two twins whose haemoglobin pattern and synthesis data at birth were similar to those of the proband of family S died in the neonatal period. The mother was assumed to be a compound heterozygte for alpha thalassaemia-2 and beta 0 thalassaemia and the father for alpha thalassaemia-1 and beta 0 thalassaemia. The homozygous state for beta 0 thalassaemia in association with the alpha thalassaemia 1 and alpha thalassaemia 2 genes results in a severe clinical picture similar to that of a homozygous beta 0 thalassaemia. The interaction between the heterozygous state for beta 0 thalassaemia and the alpha thalassaemia 1 or alpha thalassaemia 2 genes, or the combination of both, results in a haematological picture similar to that of a beta thalassaemia heterozygote.