A newly identified mutation in the complement factor I gene not associated with early post-transplant recurrence of atypical hemolytic-uremic syndrome: a case report

Atypical hemolytic uremic syndrome (aHUS), which can recur after renal transplantation, is associated with poor graft outcomes. The underlying genetic defect, namely, mutations in genes coding for the complement factor H, I (CFI), or membrane cofactor protein, greatly impacts the risk of aHUS recurrence. We report here the case of a patient with chronic renal failure due to aHUS in which screening for complement mutations, performed before wait-listing for kidney transplantation, showed a never described previously heterozygous mutation in the exon II of the CFI gene. Specifically, this mutation leads to a substitution of cytosine for guanosine at nucleotide 148, resulting in the change at amino acid 50 from arginine to proline. Subsequently, he received a renal allograft from deceased donor. Good graft function was established immediately, without clinical features of aHUS. Due to a lack of data on this mutation, we avoided prophylactic treatment for aHUS but closely monitored biochemical markers of aHUS to treat a possible recurrence. Immunosuppressive treatment was based on basiliximab, tacrolimus, steroids, and mycophenolic acid. At the time of discharge the serum creatinine was 1.4 mg/dL. Ten months after transplantation the patient is doing well without evidence of aHUS. Our case suggested that a heterozygous mutation in exon II of the CFI gene was not associated with a risk of early post-transplant aHUs recurrence adding new knowledge on complement mutations implicated in aHUS post-transplant recurrences.