GP.MOT: A novel glycophorin variant identified in a Japanese blood donor.

Background: In this study, we identified a novel glycophorin variant (GP.MOT) in a Mi -positive Japanese blood donor. The proband with this glycophorin variant was discovered by antigen screening of samples from 475,493 Japanese blood donors using monoclonal anti-Mi .

Study Design And Methods: Standard serological techniques and flow cytometry were performed. GP.MOT RBCs were examined by immunoblotting using anti-GPA, anti-MUT or anti-Mur. Genome DNA was extracted from whole blood, and the GYPA/GYPB was analyzed by polymerase chain reactions and Sanger sequencing.

Results: The MNS blood group of the proband was M + N +  S-s + with the presence of other low-frequency antigens including Mi , Mur, MUT, and KIPP. A 43-kDa molecule, which is almost equivalent in size to glycophorin A (GPA), was identified by immunoblotting using monoclonal anti-MUT and anti-Mur. Sanger sequencing clearly indicated that the proband had two different GYPA*M alleles at SNP rs62334651 (GYPA*M232 + 55A and GYPA*M232 + 55G), as well as a GYP(B-A) hybrid allele (GYP*MOT) with breakpoints located on pseudoexon 3 of GYPB from c.210 to c.219.

Discussion: We identified a hybrid glycophorin GP.MOT with the deduced unique amino acid sequence GPB (20-45)-GPΨB (46-70)-GPA (71-149), which has not been previously reported.