Missense mutations in the C-terminal portion of the B4GALNT2-encoded glycosyltransferase underlying the Sd(a−) phenotype
Sda is a high-frequency carbohydrate histo-blood group antigen, GalNAcβ1-4(NeuAcα2-3)Galβ, implicated in pathogen invasion, cancer, xenotransplantation and transfusion medicine. Complete lack of this glycan epitope results in the Sd(a−) phenotype observed in 4% of individuals who may produce anti-Sda. A candidate gene (B4GALNT2), encoding a Sda-synthesizing β-1,4-N-acetylgalactosaminyltransferase