Prenatal diagnosis of α- and β-thalassaemias in Singapore—current status

This is the authors' abstract. We don't add key points for this paper.

Prenatal diagnosis was performed in 31 pregnancies where the fetuses were at risk for either homozygous alpha(0) - or beta-thalassaemia. First-trimester prenatal diagnosis by DNA analysis using chorionic villi was carried out for 17 pregnancies at risk for homozygous alpha (0)-thalassaemia. The alpha-globin genes in fetal DNA were detected by gene mapping using restriction endonuclease mapping and hybridization with cloned alpha-globin probe. Homozygous alpha (0)-thalassaemia was detected in four fetuses and the results were subsequently confirmed by electrophoresis of the cord blood where only Hb Barts was detected. Prenatal diagnosis for beta-thalassaemia was carried out by globin chain biosynthesis using fetal blood at 18-20 weeks' gestation. Using carboxymethyl (CM) sepharose chromatography, homozygous beta-thalassaemia was predicted in six pregnancies, and one fetus carried Hb E-beta thalassaemia. The seven pregnancies were terminated and globin chain analysis using cord blood confirmed the prenatal diagnoses. The remaining seven fetuses were diagnosed as either normal or beta-thalassaemia carriers. Using DNA analysis and globin chain biosynthesis for prenatal diagnosis of homozygous alpha(0)- and beta-thalassaemia, a 100% correlation was achieved with fetuses predicted to possess the homozygous condition.