Complement factor H mutation associated with membranoproliferative glomerulonephritis with transformation to atypical haemolytic uraemic syndrome.

A patient with a history of haemolytic anaemia and membranoproliferative glomerulonephritis type 1 since childhood developed relapsing atypical haemolytic uraemic syndrome (aHUS) at the age of 18. Despite several episodes of relapsing aHUS, she was successfully treated with plasmapheresis. aHUS is strongly associated with disorders of the complement pathway. Diagnostic work-up of the patient revealed normal serum values of complement factor H, I, B and membrane cofactor protein (MCP). Genetic analysis showed a homozygous mutation in the factor H gene. Extraordinarily, the homozygous mutation in this patient causes a normal amount but hypothetically functionally defective factor H in the plasma.