LAUSR

MNS is a complex blood group system whose antigens are carried on glycophorin A (GPA), glycophorin B (GPB) and hybrid glycophorin molecules. These hybrid proteins are the results of gene recombination events at the GYPA/GYPB loci. One of the larger groups of hybrid proteins in this system are the GP(B-A-B) hybrid proteins, which often arise through gene recombination events in and around exon 3/intron 3 of GYPA, and pseudoexon 3 of GYPB. Different low-prevalence antigens are expressed on the hybrids depending on the point of crossover, and the presence of such a hybrid is often detected by aberrant expression of S and/or s antigens. We present the investigation of samples from a blood donor who had been genotyped on the HEA BeadChip array (Immucor, GA) as GYPB*03/03 but whose RBCs phenotyped S+ s+ . 1.1 | Brief methods