Simultaneous screening for beta-thalassemia mutations by chemical cleavage of mismatch.

We used the chemical cleavage of mismatch (CCM) method to screen the beta-globin gene simultaneously for Mediterranean beta-thalassemia mutations. The beta-globin gene was amplified in two segments encompassing the whole gene and hybridized to a corresponding labeled PCR product from a normal subject. All the known mutations tested were identified and discriminated. Three beta-thalassemic subjects with previously undiagnosed mutations were identified as carriers of two rare DNA changes. The inheritance of the mutations could be traced in family studies, showing the reliability of the method even for prenatal diagnosis. The beta-globin gene polymorphisms were also detected and the framework was determined for most alleles. Our results suggest further applicability of the CCM method as a means to screen a gene simultaneously for multiple mutations.