SAT, a 'new' low frequency blood group antigen, which may be associated with two different MNS variants.

A new private blood group antigen, SAT, was identified in an NFLD-Japanese woman as a result of testing 10,480 blood donors with a serum containing anti-NFLD and anti-SAT. Three other sera were subsequently also shown to contain anti-SAT. The donor's family showed that SAT is inherited as a dominant character and may be associated with a weak M antigen. Serological and immunochemical analysis revealed no other aberrations in the MNS system. Study of a second SAT+Japanese blood donor and his family suggested that SAT is associated with an unusual MNS variant resulting from a hybrid glycophorin comprising the N-terminus of glycophorin A and the C-terminus of glycophorin B. The propositus appears to be homozygous for the gene that produces the putative hybrid, which differs from previously described glycophorin (A-B) hybrids by expressing no S, s or U antigen. SAT antigen, therefore, may be associated with two different MNS variants in the only two families in which it has been identified.