C3 glomerulopathy in cystic fibrosis: a case report
#MMPMID29592796
Santoro D
; Siligato R
; Vadalà C
; Lucanto M
; Cristadoro S
; Conti G
; Buemi M
; Costa S
; Sabadini E
; Magazzù G
BMC Nephrol
2018[Mar]; 19
(1
): 73
PMID29592796
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BACKGROUND: C3 glomerulonephritis is a rare glomerulopathy characterized at renal
biopsy by C3 deposition, alone or with scanty immunoglobulins, as well as by an
electron-dense material in mesangium, subendothelial and subepithelial space. An
abnormal systemic activation of the alternative pathway of the complement cascade
is responsible for the development of the disease if triggered by several
possible environmental conditions. We report the first case in literature of a
patient affected by cystic fibrosis and C3GN. CASE PRESENTATION: Our case
involves a young woman with cystic fibrosis, who had persistent microscopic
hematuria, proteinuria and hypocomplementemia C3 for over three months. Renal
biopsy confirmed the diagnosis of C3 glomerulopathy. Complement system
dysregulation was tested and resulted in a strong terminal pathway activation
proved by high levels of sC5b-9 complex, amounting to 1588 ng/ml (normal value
400 ng/ml). Next generation sequencing (NGS) showed polymorphism in CFH (p.V62I
in SCR1) and THBD (p.A473V), already known as pathogenic for C3GN, as well as a
mutation in C3 (p.R102G) associated only with age-related macular degeneration
(AMD) so far. Treatment was based on ACE inhibitors and kidney function is
currently stable (GFR 50 ml/min, serum creatinine 1.7). CONCLUSIONS: The
co-existence of C3 glomerulopathy in a patient with CF, which is characterized by
chronic infection/inflammation, makes this case an interesting model of chronic
altered systemic activation of the alternative pathway of the complement cascade.