The Diego blood group system-an update

Abstract

The Diego system currently is composed of 19 anti¬gens: two pairs of antithetical antigens of high and low incidence and a further 15 low-incidence antigens. The assignment of all of these antigens to one system was possible following the cloning and sequencing of the band 3 (A.EI) gene. The genetic background to all the polymorphisms is the same: a single nucleotide change in the band 3 gene gives rise to an amino acid substitu¬tion in the protein. The extracellular amino acids of anion exchangers from other species are not well conserved and, therefore, the observed diversity of sequence is not unexpected and further polymorphisms are likely to be found. One should bear in mind that it may not only be the amino acid sequence that gives rise to an epitope, but also the structure and orientation of the protein may play a part. Indees, interction between two different protein, band 3 gps . fror experession. DF was always considered to be a useful anthropological marker due to its high incidence in certain Mongolian population. It is difficult to speculate the anthropological usefulness of the other antigens because of their rarity and the paucity of frequency Studies. However, WARR may be unique to Native Americans and Jn to an area incorporating southern Poland and eastern Slovakia. The rarity of these insligens isin contrast to the relative commonality of the ani-bodies defining them, notably anti-Wra The Diego system, having been a simple two-antigen system for many years, has expanded dramatically over the past few years. These studies have made a significant contribution to the characterization of band 3 topology and have helped validate the protein model. With the technology for DNA analysis firmly in place, the expansion of the Diego system seems likely to continue.