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

Giornale italiano di nefrologia : organo ufficiale della Societa italiana di nefrologia 2017 Apr

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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. Copyright by Società Italiana di Nefrologia SIN, Rome, Italy.

Citation

Luca Visconti, Valeria Cernaro, Gianluigi Ardissino, Martina Sgarbanti, Domenico Ferrara, Giuseppe Visconti, Domenico Santoro, Michele Buemi. Complement factor B mutation in atypical hemolytic uremic syndrome. Rare cause of rare disease]. Giornale italiano di nefrologia : organo ufficiale della Societa italiana di nefrologia. 2017 Apr;34(2):74-81