A beta-thalassemia lesion abolishes the same Mst II site as the sickle mutation

Digestion of DNA from a patient with homozygous beta zero thalassemia from Calabria, Italy with the restriction endonuclease Mst II produced a pattern similar to the one obtained with sickle cell trait DNA in that the Mst II site at the beta 6 position on one chromosome was abolished. We cloned the DNA from this beta-thalassemia chromosome and performed sequence analysis. The deletion of a single nucleotide (A) at the GAG codon of the beta 6 position results in a frame shift and early beta-globin chain termination. This mutation occurs on a chromosome with a haplotype similar to two other Mediterranean beta-thalassemia lesions. The Mst II enzyme is useful for prenatal diagnosis of beta thalassemia in this population.