MNS System
Definition
A blood group system comprising M and N antigens on glycophorin A (GYPA) and S and s antigens on glycophorin B (GYPB). Six common MNS phenotypes are formed by combining MM/MN/NN with SS/Ss/ss.
- Discovered
- 1927 by Landsteiner and Levine
- Chromosome location
- Chromosome 4
- Number of common phenotypes
- Six
Common questions
What antigens make up the MNS blood group system?+
The MNS system comprises four antigens: M and N on glycophorin A, plus S and s on glycophorin B. These antigens are produced by genes on chromosome 4. The system is named after the M, N, and S antigens that define it.
How many different phenotypes are possible in the MNS system?+
Six common phenotypes exist. Each person's MNS type combines their M/N genotype (MM, MN, or NN) with their S/s genotype (SS, Ss, or ss). This creates six distinct patterns used in forensic blood typing.
Why is the MNS system important in forensic science?+
The MNS system provides an independent blood group for exclusion testing and identity work. Because it segregates separately from the ABO and Rh systems, it strengthens the discriminatory power of blood group evidence.
Related terms
- Rh System
- A blood group system defined by antigens on two proteins encoded by the RHD and RHCE genes on chromosome 1. The clinically...
- ABO System
- The blood-group classification described by Karl Landsteiner in 1901: groups A, B, AB, and O, defined by antigens on red-cell surfaces and...
- Agglutination
- Clumping of red cells that occurs when antibodies in serum bind to incompatible antigens on the cell surface, cross-linking cells into visible...
- Antibody (Isohaemagglutinin)
- An immunoglobulin in plasma directed against red-cell antigens the host does not carry. Group O serum carries anti-A and anti-B; group AB...
- Antigen
- A molecule recognised by the adaptive immune system through specific binding to an antibody or T-cell receptor. Defined by immunogenicity (capacity to...
- Antigen Degradation Rate
- The rate at which an antigen becomes undetectable on a dried stain, driven by protein denaturation, microbial protease activity, UV exposure, and...
- Antithetical Antigens
- Pairs of antigens where carrying one typically excludes the other on the same protein: C and c, E and e in the...
- Bombay Phenotype (Oh, Hh)
- Y. M. Bhende, 1952, K.E.M. Hospital Mumbai. Homozygous absence of the H antigen, so neither A nor B can be expressed; types...
- Discriminating Power
- The statistical ability of a typing system to distinguish one individual from another in a given population. Expressed as the probability that...
- Glycophorin
- A family of heavily sialylated red-cell glycoproteins. Glycophorin A carries M and N antigens; glycophorin B carries S and s antigens. Both...
- ISBT
- International Society of Blood Transfusion. The authority that catalogues and numbers the 35+ recognised blood group systems.
- Secretor Status
- A genetic trait that determines whether a person expresses their ABO blood group antigens in secreted body fluids such as saliva, semen,...
Explained in these topics
- Blood Group Systems in Forensic Science: ABO, Rh, MNS and BeyondLandsteiner and Levine, 1927. Controlled by the GYPA / GYPB genes on chromosome 4. Antigens M, N, S, s.
- Rh, MNS, and Other Blood Group SystemsA blood group system comprising M and N antigens on glycophorin A (GYPA) and S and s antigens on glycophorin B (GYPB). Six common MNS phenotypes are formed by...