β+-thalassaemia in the Po river delta region (northern Italy): Genotype and β globin synthesis

Six β+-thalassaemic patients from the Po river delta region have been studied. Using synthetic oligonucleotides as specific hybridisation probes, the β+ IVS I mutation (G→A at position 108) was demonstrated. This lesion and the enzyme polymorphism pattern in the subjects examined are the same as have been described for other Mediterranean β+-thalassaemias. Antenatal diagnosis through DNA analysis of β+-thalassaemia is therefore possible. The production of β globin in a β+ homozygote and in a β+, β° 39 (nonsense mutation at codon 39) double heterozygote is approximately 20% and 10% respectively of total non-α globin synthesis. Despite some overlapping of the results, similar β globin synthesis levels have been obtained in 43 β+-thalassaemia patients. This suggests that in the Po river delta region the most common thalassaemic genes are β° 39 and β+ IVS I.