High Hb F levels in a Sardinian family: a genetic defect intermediate between HPFH Greek type and delta beta-thalassemia?

We describe an Italian family from Sardinia in which 4 subjects had high levels of HbF with normal HbA 2. In every case hematological data and erythrocyte indices were normal, globin chain synthesis was balanced and Hb F distribution among the erythrocytes was pancellular. γ chain composition studies revealed mostly Aγ chains; all these data could be in keeping with a form of HPFH Greek type. However, unlike this condition, the β gene linked to this genetic defect seems to be completely suppressed as in δβ-thalassemia. Thus we suggest that this defect has intermediate features between HPFH Greek type and δβ-thalassemia.