Hb Bart ’ s Level in Cord Blood and Deletions of a - Globin Genes

The white blood cell DNA of 36 cord blood samples with Hb Bart’s in the red blood cells was studied for a-globin gene deletions by hybridization of DNA fragments digested by the restriction endonucleases Eco RI, Hpa I. Bam HI, and Bgl II. All 16 DNA samples from cord blood with Hb Bart’s below 3% and no other abnormal hemoglobin had one a-globin gene deletion (athal2), except one which had two a-globin gene deletions (athal1). Most of the athal2 were of the rightward deletion athal2 genotype. Two new types of athal2 variation were found, probably due to a polymorphism somewhere in an area outside the a-globin gene. All