Résumé
Objective To investigate the clinicopathological features and treatment of children with C3 glomerulopathy (C3 G).Methods Seven children diagnosed as C3 G by clinical and pathological characteristics were enrolled in this study.The clinicopathological data and the prognosis were analyzed.Results Of the 7 cases,4 cases were female and 3 cases were male,with the mean age of (7.7-± 3.1) years old (1.5-10.4 years old) at onset,the duration from onset to renal biopsy was (3.4 ± 2.4) months (1-6 months) and 1 of them had a second renal biopsy 4.2 years later,and mean age was (8.4 ± 3.6) years old (1.8-13.3 years old) on diagnosis.Clinical features:among the 7 patients,6 cases had hematuria,among them 1 case had gross hematuria and 5 cases had microscopic hematuria;6 cases had low level of serum complement C3,5 cases had heavy proteinuria and low serum albumin,and anemia was observed in 2 cases respectively.Five cases had complement factor H and H factor antibody by examination,and 1 of them had low serum factor H,but none of them had serum antibody to factor H.Four cases had genetic evaluation,and only 1 case revealed risk variants in the C3 gene(R304R,T612T,V807V,A915A,P1632P)and CFH gene(p.H402Y,p.E936D).Clinically,4 cases were diagnosed as nephrotic syndrome of nephritis type,2 cases were diagnosed as nephritic syndrome,and 1 case was diagnosed as nephrotic syndrome of simple type.Immunofluorescence study showed that all the cases had intense deposition of C3,and 6 cases were accompanied by the deposition of immunoglobulin.Under light microscopy,3 cases showed the feature of membrane proliferative glomemlonephritis,2 cases with endocapillary prolifera-tive glomerulonephritis,1 case with mesangial proliferative glomerulonephritis,and 1 case with endoeapillary proliferative IgA nephropathy.Under electron microscopy,3 cases who had typical ribbon-like dense deposits in glomerular basement membrane were of dense deposit disease,and the rest were C3 glomerulonephritis.All patients had steroid and immune inhibitor treatment,and during the follow-up stage of (2.6 ± 1.8) years(1.1-5.6 years),4 cases showed normal urinalysis,2 cases had microproteinurine and microscopic hematuria,and 1 case had urinary protein ± to + + and microscopic hematuria.Conclusions C3G has variety of pathological-clinical manifestation.Interpretation of individual cases depends on integration of information from the biopsy together with clinical,serological,and genetic features.Patients with steroid and immune inhibitor treatment had some clinical improvement of their urinalysis.