<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Unlike most blood group antigen pairs, the I and i antigens are not antithetical (produced by allelic pairs) but, rather, they are reciprocal. The I antigen is formed by the action of an enzyme (a glycosyltransferase), which adds branches onto the i antigen. Thus, branched I antigen is formed at the expense of its precursor, the linear i antigen. The antigens are present on all blood cells and have a wide tissue distribution. Soluble I antigen is found in milk, saliva, and amniotic fluid, and a small amount is in plasma. The function of these antigens is unknown but the I antigen has a decreased expression and the i antigen has a concomitant increased expression in conditions that result in increased hematopoiesis. The gene encoding the branching transferase has been cloned and sequenced, and the mechanism underlying the i adult phenotype with and without association with cataracts has been elucidated. <bold><italic>Immunohematology</italic> 2004;20:249–252.</bold></p></abstract>

Unlike most blood group antigen pairs, the I and i antigens are not antithetical (produced by allelic pairs) but, rather, they are reciprocal. The I antigen is formed by the action of an enzyme (a glycosyltransferase), which adds branches onto the i antigen. Thus, branched I antigen is formed at the expense of its precursor, the linear i antigen. The antigens are present on all blood cells and have a wide tissue distribution. Soluble I antigen is found in milk, saliva, and amniotic fluid, and a small amount is in plasma. The function of these antigens is unknown but the I antigen has a decreased expression and the i antigen has a concomitant increased expression in conditions that result in increased hematopoiesis. The gene encoding the branching transferase has been cloned and sequenced, and the mechanism underlying the i adult phenotype with and without association with cataracts has been elucidated. Immunohematology 2004;20:249–252.

The gene encoding the I blood group antigen: review of an I for an eye

Immunohematology

{"article-title":"The gene encoding the I blood group antigen: review of an I for an eye"}

Unlike most blood group antigen pairs, the I and i antigens are not antithetical (produced by allelic pairs) but, rather, they are reciprocal. The I antigen is...

The gene encoding the I blood group antigen: review of an I for an eye

Published Online: May 18, 2020

Page range: 249 - 252

DOI: https://doi.org/10.21307/immunohematology-2019-458

Keywords
I blood group, blood groups, human blood groups, carbohydrate antigen, cataracts

© 2004 M.E. Reid et al., published by Sciendo

The gene encoding the I blood group antigen: review of an I for an eye

Published Online: May 18, 2020

Page range: 249 - 252

DOI: https://doi.org/10.21307/immunohematology-2019-458

KeywordsI blood group, blood groups, human blood groups, carbohydrate antigen, cataracts

© 2004 M.E. Reid et al., published by Sciendo

Keywords
I blood group, blood groups, human blood groups, carbohydrate antigen, cataracts