RARE VARIANT OF COMPLEMENT C4 IS SEEN IN HIGH FREQUENCY IN PATIENTS WITH PRIMARY GLOMERULONEPHRITIS

Abstract 59 unselected patients with primary glomerulonephritis were phenotyped for alleles of the MHC-linked complement genes, C4A, C4B, and BF. A rare variant of the C4B locus, C4B*2·9, was found in 25% of these patients compared with only 2% of the normal population—a relative risk of 22·1 for glomerulonephritis in individuals with this variant. Subdivision of patients by histological classification of glomerulonephritis revealed a significant association of C4B*2·9 with the membranoproliferative form. There were no significant associations between primary glomerulonephritis or its subtypes and the other HLA markers tested.