A 12-YEAR PREVENTIVE PROGRAM FOR BETA-THALASSEMIA IN NORTHERN SARDINIA

From 1980 to 1991, 6.3% of the adult population of the province of Sas sari, Northern Sardinia, underwent voluntary beta-thalassemia screenin g. Of the 28 000 subjects examined, 15.7% proved to be heterozygotes f or beta-thalassemia. In addition, the screening of 7500 students in 26 villages in Sassari province fixed the frequency of beta-thalassemia in this part of Sardinia at 10.4%. Of the 539 couples at risk to be ex pected from this figure, the screening detected 43% (234). The data su ggest that inductive screening played a major role in the efficiency o f this preventive beta-thalassemia program. Follow up of 221 pregnanci es found to be at risk for homozygous beta-thalassemia and referred to the Antenatal Diagnosis Service, Cagliari, Southern Sardinia, showed that antenatal diagnosis was carried out in 80% of them. The overall p ercentage 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 cou ples at risk required globin chain synthesis and molecular analyses to define the precise beta-thalassemia genotype. Heterogeneous ''mild'' beta-thalassemia mutations as well as coexisting delta-thalassemia wer e found in silent type I and type II beta-thalassemia carriers which, without chain synthesis and DNA investigations, would have escaped det ection.