Prenatal diagnosis of hemoglobinopathies

Detection of any disease in utero requires the safe acquisition of the appropriate fetal tissue for study, and development of sensitive and accurate assays that distinguish affected individuals from carriers and normals. The development of acceptable technology requires samples from normal as well as affected fetuses. Such samples can be ethically obtained at the time of termination of the pregnancy as long as the sampling does not influence the decision regarding termination. The safety and reliability of sample acquisition improve as the obstetrician gains experience. These principles were employed in the development of prenatal diagnosis of the hematologic diseases discussed above, and led to rapid application of the techniques as soon as the methods were ready. The next advance in prenatal diagnosis of hemoglobinopathies will occur when procedures are developed that will regularly allow detection of the primary gene defects or of linked polymorphisms in common forms of β-thalassemia in amniotic cell DNA and/or permit induction of expression of dormant globin genes in fetal fibroblasts either by cell fusion or biochemical manipulations.