Prenatal diagnosis of homozygous beta-thalassaemia.

In two pregnancies at risk for homozygous beta+ and beta0 thalassaemia, fetal blood mixed with maternal blood was obtained by placental aspiration and was purified to over 90% purity by differential agglutination with anti-i antibodies. Study of globulin-chain synthesis showed absence of beta-globulin chain in both fetuses. The diagnosis of homozygous beta-thalassaemia was made and was confirmed after the pregnancies were terminated. Thus, the defect in beta-globulin-chain synthesis in homozygous beta-thalassaemia is expressed in utero, and prenatal diagnosis is possible.