Atypical hemolytic uremic syndrome

Table 1 Percentage of patients with decreased C3 plasma concentration in the various subgroups of atypical hemolytic uremic syndrome

	CFH mutation	CFI mutation	MCP mutation	C3 mutation	CFB mutation	THBD mutation	Anti -CFH Ab	None
Decreased C3 concentration (< 2SD) (% patients)	30-50%	20-30%	0-27%	70-80%	100%	50%	40-60%	up to 20%

Normal C3 plasma concentration does not eliminate the presence of a mutation in the complement system or of anti- CFH antibodies. Conversely, decreased C3 level signs the presence of a complement abnormality.
CFH: factor H; CFI: factor I; MCP: membrane cofactor protein; CFB: factor B; THBD: thrombomodulin; Ab, antibodies.