Molecular Characteristics of a Non-deletion α-Thalassaemia of the Po River Delta

The form of α-thalassaemia of the Po river delta presents haematological and globin biosynthetic characteristics similar to α-thalassaemia-1 but never gives rise to Hb H disease nor to hydrops foetalis. In α-thalassaemic subjects originally from this region globin mRNA translation and α-globin gene arrangement have been investigated. The data obtained indicate that α-globin synthesis and reticulocyte α-globin mRNA are reduced by one fourth; in addition, since the defect in α-globin synthesis does not change with cell ageing, a possible instability of α-globin mRNA is excluded. Restriction enzyme analysis of the DNA shows a normal α-globin gene organization. This form of α-thalassaemia is therefore of the non-deletion type; its molecular lesion is either at the level of α-globin mRNA transcription or processing. The fact that this, as well as other forms of non-4eletion α-thalassaemia, have a phenotipic expression similar to α-thalassaemia 1 is discussed.