Complement factor B mutation in atypical hemolytic uremic syndrome. Rare cause of rare disease

Luca Visconti, Valeria Cernaro, Gianluigi Ardissino, Martina Sgarbanti, Domenico Ferrara, Giuseppe Visconti, Domenico Santoro, Michele Buemi

Research output: Contribution to journalArticlepeer-review


Hemolytic uremic syndrome (HUS) is a rare disease characterized by microangiopathic hemolysis, platelet consumption and multiple organ failure with predominant renal involvement. In the most of cases (85-90%), it is associated with enteric infection due to Shiga-toxin or verocytotoxin (STEC-VTEC)-producer Escherichia coli. Rarely, in about 10-15% of cases, HUS develops in the presence of a disorder of alternative complement pathway regulation and it is defined atypical (aHUS). We describe the case of a 65-year-old man who came to our attention with a clinical presentation of aHUS and a clinical course characterized by rapidly progressive acute renal failure (ARF), which required renal replacement treatments, and by a stable clinical picture of hematological impairment as a marker of a non-severe and self-limiting form. The clinical and laboratory course allowed us not to perform specific therapies such as plasma exchange and/or block of the complement with eculizumab. Less than two weeks after hospital admission, there was a gradual recovery of renal function with spontaneous diuresis and hematological remission. Genetic screening has revealed a heterozygous mutation in the complement factor B (CFB) that is not described in the literature and therefore not yet characterized in the genotype/phenotype correlation, also for the extreme rarity of the forms associated with CFB alteration. In conclusion, the presence of a new mutation in the CFB, such as the one described in our case, is probably associated with the development of aHUS but has not led to a poor prognosis, as generally reported in the literature for known variants of the CFB.

Original languageEnglish
Pages (from-to)74-81
Number of pages8
JournalGiornale italiano di nefrologia : organo ufficiale della Societa italiana di nefrologia
Issue number2
Publication statusPublished - Apr 1 2017


  • Acute kidney injury
  • Atypical hemolytic uremic syndrome
  • Complement factor B mutations
  • Thrombotic microangiopathy

ASJC Scopus subject areas

  • Medicine(all)


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