Prenatal diagnosis of thalassemia and of the hemoglobinopathies; a review.

Prenatal diagnosis of thalassemia and of the hemoglobinopathies is now accepted as an effective measure to reduce the impact of these diseases in populations where they occur in high frequencies. The procedure has been carried out on more than 5,000 cases over the past decade. Evaluation of the results shows a significant decrease of the yearly number of affected newborns and reflects a considerable gain in economic and medical resources. Methodology has improved over the years so as to make the procedure safer, faster, and less expensive. Among recent advances, gene mapping on trophoblast DNA (as early as the 9th week of pregnancy) represents a major step which will gradually replace conventional procedures (performed during the 18-20th week of pregnancy) in concerned laboratories.