C4 allotyping 13 homozygous C2-deficient individuals demonstrated 23 of 25 haplotypes to be of the relatively rare type C4A4 B2. This is of the same magnitude as the association of C2Q0 with HLA-DW2/DR2.
Z L Awdeh, D D Raum, D Glass, V Agnello, P H Schur, R B Johnston Jr, E W Gelfand, M Ballow, E Yunis, C A Alper