Save BIG with $9.99 .COMs from GoDaddy!
MNS system = Chromosome 4 (antigens are carried on Glycophorins A and B). M, N, S, s and U. Anti-M and Anti-N are IgM and thus are not really significant. (anti-N formaldehyde in dialysis patients). Anti-S and anti-s are clinically significant. "U" antigen stood for "universal" but 0.01% of people lack it, mostly of African descent.