Xg glycoprotein (XG)

Xg glycoprotein (abbreviation XG), also known as Glycoprotein Xg, is a cell-surface protein responsible for the XG blood group antigen in humans[1][3][6][8]. The gene encoding this protein is located at the pseudoautosomal boundary on the short arm of the X chromosome, with a truncated copy on the Y chromosome that is not functionally expressed[3][6][8]. Xg glycoprotein is structurally related to CD99 and is involved in cell adhesion processes, specifically in T cell and neutrophil extravasation and homotypic cell–cell interactions[2]. It does not belong to classical classes of therapeutic targets such as receptors, enzymes, transporters, or ion channels, but rather functions as a blood group antigen important in transfusion medicine[1][3][8]. There are no drugs known to target Xg glycoprotein, nor is it a current focus as a therapeutic target, but its antigenic properties are clinically relevant as a biomarker for blood group determination[1][3][8]. There is no evidence suggesting it is directly implicated in major disease mechanisms or that there are safety concerns relating to it as a drug target[3]. Its principal clinical utility lies in immunohematology and genetic studies of blood group antigens.

Other names

Glycoprotein XgXGPBDXProtein PBDXXg blood groupXg(a) antigenXG blood group antigenXG blood group gene