MNS antigen system

Red blood cell with MNS antigens on its surface

The MNS antigen system is a human blood group system based upon two genes (glycophorin A and glycophorin B) on chromosome 4. The MNS system is one of the five major human blood group systems recognized by the International Society of Blood Transfusion, alongside the ABO, Rh, Kell, and Duffy systems.

History

The MNS antigen system was first discovered in 1927 by Karl Landsteiner and Philip Levine, who identified the M and N antigens. The S and s antigens were later discovered in 1947.

Genetics

The MNS system is controlled by two closely linked genes located on chromosome 4, known as glycophorin A (GYPA) and glycophorin B (GYPB). These genes encode the M, N, S, and s antigens.

Antigens

The MNS system includes numerous antigens, the most important of which are M, N, S, s, and U. The M and N antigens are produced by the GYPA gene, while the S, s, and U antigens are produced by the GYPB gene.

Clinical Significance

The MNS antigens are clinically significant in blood transfusion and pregnancy. Antibodies to these antigens can cause hemolytic disease of the newborn (HDN) and hemolytic transfusion reaction (HTR).

See Also

• Blood type
• Blood transfusion
• Hemolytic disease of the newborn
• Hemolytic transfusion reaction