A Japanese Family with Two Sisters Apparently Homozygous for M^k

Abstract

Two Japanese sisters with consanguineous parents have M —N — En(a —) Wr(a — b — ) S — s — U— red cells and are therefore apparently homozygous for M^k; the third reported family with members of this genotype. The serum of the proposita (ORCMK) contained anti-En^aTS, anti-En^a FR and possibly anti-Wr^b, whereas the serum of her M^kM^k sister contained no atypical antibodies. Total absence of sialoglycoproteins α and δ from red cell membranes of an M^k homozygote was demonstrated by lactoperoxidase-catalysed radioiodination of accessible tyrosine residues with subsequent SDS polyacrylamide gel electrophoresis and autoradiography, and by use of a monoclonal antibody directed at the cytoplasmic portion of α-sialoglycoprotein.