We present a case of chronic thrombotic microangiopathy (TMA) after kidney transplantation in a recipient who had been classified as hypertensive ESRD and found to have a genetic defect in CD46, a transmembrane protein that regulates complement activation, indicating atypical hemolytic uremic syndrome (HUS).
Patients with a Complement Factor H mutation had reduced ESRD-free survival, whereas Membrane Cofactor Protein mutation was associated with longer ESRD-free survival.
Among patients with CFH or CFI mutations, the presence of mutations in other genes did not modify prognosis; in contrast, 50% of patients with combined MCP mutation developed end stage renal failure within 3 years from onset compared with 19% of patients with an isolated MCP mutation.
Patients carrying MCP mutations have a favorable clinical outcome in comparison to those with factor H (CFH) or factor I (IF) mutations, which lead in most cases to end-stage renal failure.