Background：

Glycophorins A (GYPA) and B (GYPB) are major sialoglycoproteins of the human erythrocyte membrane which bear the antigenic determinants for the MN and Ss blood groups. GYPB gene consists of 5 exons and has 97% sequence homology with GYPA from the 5’ UTR to the coding sequence encoding the first 45 amino acids. In addition to the M or N and S or s antigens， that commonly occur in all populations， about 40 related variant phenotypes have been identified. These variants include all the variants of the Miltenberger complex and several isoforms of Sta; also， Dantu， Sat， He， Mg， and deletion variants Ena， S-s-U- and Mk. Most of the variants are the result of gene recombinations between GYPA and GYPB. Alternate splicing results in multiple transcript variants.