Abstract
Background
Complement factor B gene (
CFB
) is an important component of the alternate pathway of complement activation that provides an active subunit that associates with C3b to form the C3 convertase, which is an essential element in complement activation. Among the complement-associated disorders, mutations and pathogenic variants in the
CFB
gene are relatively rare phenomena. Moreover, mutated
CFB
affiliation with immune-complex diffuse membranoproliferative glomerulonephritis (IC-MPGN) and atypical hemolytic uremic syndrome (aHUS) are considered a highly rare occurrence.
Case presentation
We describe the clinical presentation, course, and pathological findings in a 7-year-old boy who has confirmed
CFB
heterozygous variants with pathological features compatible with IC-MPGN. Mutational analysis revealed a heterozygous variant p.Glu566Arg in exon 13 of the
CFB
gene. The patient did not respond to steroids and mycophenolate mofetil (MMF) therapy but responded clinically and biochemically to eculizumab treatment. This is the first case report of
CFB
alteration associated with IC-MPGN and aHUS that was successfully treated with eculizumab.
Conclusions
Heterozygous variants in the
CFB
gene can be pathogenic and associated with IC-MPGN and aHUS. Early diagnosis and prompt management can be essential in preventing end-stage renal disease. Eculizumab may provide an effective modality of treatment.