Blood Group, Globoside System
A number sign (#) is used with this entry because the globoside blood group system (GLOB), defined by the P antigen, is determined by activity of the B3GALNT1 gene (603094) on chromosome 3q25.
DescriptionThe P antigen, globoside-4 (Gb4), is a prominent glycosphingolipid on human erythrocytes (summary by Okajima et al., 2000).
P-related IgG and IgM antibodies are implicated in hemolytic transfusion reactions, hemolytic disease of the newborn, and spontaneous abortion (see 614389) (summary by Thuresson et al., 2011). Anti-P antibodies are also implicated in paroxysmal cold hemoglobinuria (PCH), a syndrome often seen in children after viral infection. In PCH, anti-P is also known as the Donath-Landsteiner antibody (Cantin and Lyonnais, 1983; Spitalnik and Spitalnik, 1995).
Molecular GeneticsOkajima et al. (2000) determined that the P antigen (Gb4) is synthesized from the P(k) antigen by the B3GALNT1 gene. The P(k) antigen is part of the P1PK blood group system (111400).