Linkage Relationship of C2 Deficiency, HLA and Glyoxalase I Loci1

Abstract

Immunogenetic analysis of a homozygous [complement] C2-deficient individual and family members demonstrated linkage of HLA-A25, B18 and C2o. HLA-D typing showed that 5 members typed with homozygous Dw2 typing cells from an individual with C2 deficiency but not with Dw2 typing cells from 2 individuals with normal C2. The homozygous C2-deficient propositus and brother were HLA-A and B homozygous, but were heterozygous at the HLA-D and glyoxalase loci. In this family, the C2o gene is linked with 2 distinct haplotypes: HLA-A25, B18, Dw2, GLO1 and HLA-A25, B18, D unknown, GLO2. An ancestral recombinant event may have occurred between the C2o locus and HLA-D locus in which C2o segregated with HLA-B. The locus for the C2o gene may map between HLA-B and HLA-D on the 6th chromosome.