A New Rare Blood Group Antigen, ‘FAR’, Probably Linked to the MNSs System

Abstract

A new, rare antigen, FAR, was discovered in connection with a hemolytic disease of the newborn. This very rare antigen was not encountered in 14,273 Caucasians tested. It is probably linked to the MNSs system (p<0.004). The anti-FAR antibody, which is of immune origin, is also very rare: it has been sought unsuccessfully in 541 sera. The identification of this antigen provides further evidence of a comparatively high mutation rate in some sites on the MNSs locus and of its practical interest in both pathology and human genetic studies.

MNS Blood Group System

“…The gene producing Far antigen appeared to be aligned with Ns in one family [238,417] and with MS in another [239,418] , although neither family proves close linkage with MNS . Far is resistant to trypsin, papain, and fi cin [239,254] .…”