Application of natural and amplification-created restriction sites in prenatal and preimplantation diagnosis of beta-thalassemia.

We attempted the strategy of natural and amplification-created restriction sites for early prenatal and preimplantation diagnosis of Chinese beta-thalassemia. Mutagenesis primers were designed for 11 mutations reported for the Chinese population. The diagnosis was established after polymerase chain reaction and digestion of products by specific enzymes. The results were confirmed by direct sequencing of enzymatically amplified double-stranded DNA. The beta-globin gene was amplified from triploid embryos and isolated blastomeres using mismatched primers. The mutant and normal alleles can be distinguished clearly by this new method. Early prenatal diagnosis was successfully achieved in 9 cases. The beta-globin gene was successfully amplified from single blastomeres and tripronuclear embryos with mismatched primers. Natural and amplification-created restriction sites are a reliable method for rapid prenatal diagnosis of beta-thalassemia. Furthermore, the strategy provides a possible approach for the preimplantation diagnosis of beta-thalassemia.