A 12-year preventive program for β-thalassemia in Northern Sardinia

From 1980 to 1991, 6.3% of the adult population of the province of Sassari, Northern Sardinia, underwent voluntary β-thalassemia screening. Of the 28 000 subjects examined, 15.7% proved to be heterozygotes for β-thalassemia. In addition, the screening of 7500 students in 26 villages in Sassari province fixed the frequency of β-thalassemia in this part of Sardinia at 10.4%. Of the 539 couples at risk to be expected from this figure, the screening detected 43% (234). The data suggest that inductive screening played a major role in the efficiency of this preventive β-thalassemia program. Follow up of 221 pregnancies found to be at risk for homozygous β-thalassemia and referred to the Antenatal Diagnosis Service, Cagliari, Southern Sardinia, showed that antenatal diagnosis was carried out in 80% of them. The overall percentage of couples refusing antenatal diagnosis was 10.8%, but over the years the acceptance rate for the procedure increased from 87% to 96%. Atypical hematological findings in 1.5% of 468 members of the couples at risk required globin chain synthesis and molecular analyses to define the precise β-thalassemia genotype. Heterogeneous “mild”β-thalassemia mutations as well as coexisting δ-thalassemia were found in silent type I and type II β-thalassemia carriers which, without chain synthesis and DNA investigations, would have escaped detection.