[Familial glomerulonephritis and hereditary deficiency of C2].

The association between glomerulonephritis and hereditary C2 complement deficiency has been found in 4 out of 8 children of a family. The hemolytic complement (CH50) was much decreased in homozygot subjects and slightly decreased in heterozygot. C1q, C4, C3, C5, C1s INA were normal, the C2 was found at an intermediate or null rate; CH50 could be reconstitued by purified human C2. The C2 deficiency genes were associated with HLA A10 B18 (father) and HLA A29 B18 (mother) haplotypes but HLA D allels were different on the 2 haplotypes. The C2 deficiency appears to lead to an increased susceptibility to immune-complexe diseases, specially to glomerulonephritis.