Homozygous C3 deficiency: Detection of C3 by radioimmunoassay

Hereditary Deficiency of the Third Component of Complement in Two Sisters With Systemic Lupus Erythematosus‐like Symptoms

“…The present patients were quite different from others with C3 deficiencies described previously (6)(7)(8)(9)24) in regard to the clinical manifestations of the affected individual. The symptoms of the 2 sisters were similar.…”

“…The mode of inheritance of C3 in the family would be consistent with an autosomal codominant trait as reported in other C3 deficiencies (8,9,24,27).…”

“…However, there have been no reports of a case with SLE or lupus-like syndromes associated with C3 deficiencies. The previously reported C3 deficiencies (6)(7)(8)(9) were associated with recurrent, severe, and occasionally life-threatening infections with onset in infancy or early childhood. In our patients, the elder sister had experienced recurrent bronchitis only in her childhood, and the younger sister had no episodes of that kind of infection.…”

“…diseases, complement deficiencies are generally divided into three groups (1): 1) deficiencies of the earlyacting complement components (Cl, C4, and C2) are frequently associated with systemic lupus erythematosus (SLE) or other rheumatic diseases (3); 2) deficiencies of the late-acting complement components (CS-C8) are associated with increased susceptibility to infections, especially to Neisseria infections (43); and 3) in the cases of C3 deficiencies, recurrent bacterial infections frequently occur (6)(7)(8)(9). We found no previous report on C3 deficiency associated with SLE or lupus-like syndrome.…”

Genetic control of the eighth component of complement.

“…In this family, children of heterozygous C8-deficient parents are described in which one presumed HLA-C8 deficiency crossover must have occurred on the hypothesis of linkage. The (36) contained _20 ng/ml of C3 (37). Serum from a homozygous C5-deficient person (29,30) Isoelectricfocusing in thin-layer polyacrylamide gel.…”