[4] Complement deficiency has historically been associated with early, severe bacterial infections among children.

More than half of 40 C2D patients in a study had Streptococcus pneumoniae-related invasive infection, primarily meningitis or sepsis.

[9] Clinical manifestations of this SLE-like illness include fever, rash, arthritis, and glomerulonephritis.

Renal and neuropsychiatric disease, on the other hand, is thought to be uncommon in these SLE patients.

[4] C2 deficiency has also been linked to rheumatic diseases such as membrane glomerulonephritis,[6] Henoch-Schonlein purpura,[12] and dermatomyositis.