Serum Complement ‘Supergenes' of the Major Histocompatibility Complex in Man (Complotypes)

Abstract

The loci for the complement proteins C2 [complement component 2] and BF, and the 2 loci for C4 are closely linked to one another. In many hundreds of meioses, no crossing over has been detected between these loci. The alleles of these 4 loci occur in specific combinations not predicted by their gene frequencies in much the same way as alleles of the Rh and MNS systems. These units are termed complotypes. There are 14 complotypes with frequencies > 1% in 2 study populations of normal 6th chromosomes from Caucasians. Since they are also intimately associated with HLA-DR, complotypes may be important in screening programs for transplantation.