Glycophorins A (GYPA; this protein) and B (GYPB) are major sialoglycoproteins of the human erythrocyte membrane which bear the antigenic determinants for the MN and Ss blood groups.

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.

GypB can be found only in gorillas and some of the higher primates suggesting that the duplication events occurred only recently.

These have arisen largely as a result of mutations within the 4 kb region coding for the extracellular domain.

These include the antigens Mg, Dantu, Henshaw (He), Miltenberger, Nya, Osa, Orriss (Or), Raddon (FR) and Stones (Sta).

[7] The Dantu antigen has an apparent molecular weight of 29 kilodaltons (kDa) and 99 amino acids.

The Miltenberger (Mi) subsystem originally consisting of five phenotypes (Mia, Vw, Mur, Hil and Hut)[12] now has 11 recognised phenotypes numbered I to XI (The antigen 'Mur' is named after to the patient the original serum was isolated from - a Mrs Murrel.)

The name originally given to this complex refers to the reaction erythrocytes gave to the standard Miltenberger antisera used to test them.

[13][14] Mi-II is due to a mutation at amino acid 28 (threonine to lysine:C->A at nucleotide 83).

This also explains the loss of a high frequency antigen ((EnaKT)) found in normal glycophorin A which is located within the residues 46–56.

[22] Peptide constructs representative of Mia mutations MUT and MUR have been attached onto red blood cells (known as kodecytes) and are able to detect antibodies against these Miltenberger antigens[23][24][25] Although uncommon in Caucasians (0.0098%) and Japanese (0.006%), the frequency of Mi-III is exceptionally high in several Taiwanese aboriginal tribes (up to 90%).

[29] Osa (MNS38) is due to a mutation at nucleotide 273 (C->T) lying within exon 3 resulting in the replacement of a proline residue with a serine.

[30] Nya (MNS18) is due to a mutation at nucleotide 194 (T->A) which results in the substitution of an aspartate residue with a glutamate.

[32] The Wright b antigen (Wrb) is located on glycophorin A and acts as a receptor for the malaria parasite Plasmodium falciparum.

[34] The erythrocyte binding antigen 175 of P. falciparum recognises the terminal Neu5Ac(alpha 2-3)Gal-sequences of glycophorin A.

[42] This article incorporates text from the United States National Library of Medicine, which is in the public domain.