Molecular basis and prenatal diagnosis of beta-thalassemia.

The molecular characterization of mutations producing beta-thalassemia in world populations is nearing completion. We expect that new rare alleles in thoroughly studied groups and other alleles in less studied groups, eg, inhabitants of New Guinea, Latin America, and certain Pacific Islands, will be found. Knowledge of the molecular basis of the disease and new technology that allows rapid detection of single nucleotide changes in genomic DNA have led to the reality of prenatal diagnosis by direct mutation detection even in the heterogeneous US population. Programs aimed at prevention of beta-thalassemia should be facilitated by these developments.