A novel c.1664G > T(p.Gly555Val) mutation in the KEL gene encoding the Kmod phenotype

T he Kell system offers one of the clinically significant blood groups in transfusion and contains more than 30 antigens. Rarely, Kell antigens are weakly expressed on red blood cells (RBCs) and have been classified as the Kmod phenotype. 1 The quantity of Kmod is decreased in the Kell glycoprotein. Adsorption and elution tests are required for the detection of Kmod. Reportedly, Kmod displays the enhanced Kx activity, and certain Kmod individuals produce an alloantibody against the Ku antigen in the transfusion. Lately, Kmod phenotypes have been intensively genotyped and classified as KEL*01 M.01, KEL*02 M.01 up to KEL*02 M.11. In this study, we identified Kmod phenotype from a Japanese blood donor in the routine tests and identified this as a novel allele for the KEL gene.