Structural basis for red cell phenotypic changes in newly identified, naturally occurring subgroup mutants of the human blood group B glycosyltransferase.
BACKGROUND: Four amino-acid-changing polymorphisms differentiate the blood group A and B alleles. Multiple missense mutations are associated with weak expression of A and B antigens but the structural changes causing subgroups have not been studied. STUDY DESIGN AND METHODS: Individuals or families having serologically weak B antigen on their red cells were studied. Alleles were characterized by s