Complement Factor H and Complement Factor H-Related Protein 5 Mutations Associated with Atypical Hemolytic Uremic Syndrome in a Systemic Lupus Erythematosus Patient: Efficacy of Eculizumab

The pathophysiology of aHUS involves endothelial injury caused by uncontrolled activation of the alternative complement pathway mostly due to mutations in genes coding for regulatory and activatory proteins (1-3). Mutations in the CFH/CFHR gene cluster have been reported in other disorders including C3 glomerulopathy, SLE, and age related macular degeneration (4,5). CFH gene mutation is the most common one with a frequency of 12-20% in sporadic, and 32-42% in familial cases (6-9). In SLE patients, certain mutations in the regulatory complement proteins related with aHUS have been reported to increase susceptibility to SLE and early onset of nephritis (10,11).