Multiple sclerosis: immunogenetic analyses of sib-pair double case families. II. Studies on the association of multiple sclerosis with C2, C4, BF, C3, C6, and GLO polymorphisms.

The complement component polymorphisms of C2, C4, BF, C3, C6, and the enzyme polymorphism GLO were studied in 13 sib-pair double case families with multiple sclerosis. A significant association was seen between MS patients and the C4 haplotype A4,B2 as compared with their healthy siblings. This finding seems to parallel reports on C2 hypocomplementemia in MS patients since C4 A4,B2 in normal individuals was also seen to be in linkage disequilibrium with the C2 deficiency allele (C2QO) by other investigators.