Partial deletion of the 5' beta-globin gene region causes beta zero-thalassemia in members of an American black family.

Restriction endonuclease mapping defined a partial deletion of about 1.35 kb in the beta-globin gene of a black American patient with hemoglobin S-beta zero-thalassemia and in his uncle with a beta zero-thalassemia trait. The 5' endpoint of the deletion is about 600 bases upstream from the cap site, and the 3' endpoint lies within about 500 bases from the 5' splice junction of the second intervening sequence. The deletion is different from that of a previously reported Indian beta zero-thalassemia allele, where 0.6 kb is deleted at the 3' end of the beta-globin gene.