Yt antigen system

The Yt antigen system (also known as Cartwright) is present on the membrane of red blood cells and helps determine a person's blood type. The antigens are found on the protein acetylcholinesterase, an enzyme which helps break down acetylcholine.^[1] The Yt system features two alleles, Yt(a) and Yt(b). Antibodies against the Yt system can lead to transfusion reactions such as hemolytic anemia.