Successful application of prenatal diagnosis in a pregnancy at risk for homozygous beta-thalassemia.

A Sicilian couple whose first child had homozygous beta-+-thalassemia requiring monthly transfusion requested prenatal diagnosis during the second pregnancy. Fully informed consent was obtained. The placenta was localized by ultra-sound at the 20th week of gestation, and was aspirated with a 20-gauge needle. Samples containing fetal red cells were obtained, and studies of globinchain synthesis showed a normal beta/gamma synthesis ratio for this gestational age. The conclusion that the child was not affected by beta-thalassemia was confirmed when an infant not affected with homozygous of heterozygous beta-thalassemia was born at term. Although more experience with this approach is necessary, this study demonstrates that prenatal diagnosis or exclusion of beta-thalassemia and sickle-cell anemia is feasible.