A 'silent', new polymorphism of factor H and apparent de novo atypical haemolytic uraemic syndrome after kidney transplantation.

The pathophysiology of atypical haemolytic-uraemic syndrome (aHUS) occurring de novo after renal transplantation may include genetic mutations of regulators of complement activation, but they are still rarely determined. A 41-year-old female renal transplant recipient presented two very different episodes of thrombotic microangiopathy. The first episode was associated with antibody-mediated rejection and the second was an isolated, acute aHUS, successfully treated with eculizumab. The diagnosis included a genetic analysis and we found a synonymous variant in the Complement Factor H (CFH) gene, c2634C>T (p.His878=) and low factor H (FH) activity during both events. In conclusion, the diagnosis of aHUS should be considered when TMA is associated with an AMR episode. In this setting, a silent polymorphism of factor H may be responsible for these rare cases of "de novo" aHUS after transplantation.