目的 探讨儿童C3肾小球病（C3G）的临床表型、病理特征、基因变异特点及治疗预后情况，为临床精准诊疗提供参考依据。方法 回顾性分析2021年7月至2024年3月于肾脏内科收治的4例C3G患儿的临床病理资料及基因检测结果，同时检索并总结国内外报道的中国儿童C3G的临床特点及转归。结果 纳入的4例C3G患儿男女各2例，发病年龄10~12岁，所有患儿均以肾病综合征合并血尿起病，其中3例就诊时已伴肾功能不全。实验室检查显示4例患儿外周血补体C3均降低（0.9~1.8 g/L），2例合并C4下降，膜攻击复合物（C5b-9）均升高，肾组织病理均表现为弥漫性系膜细胞和基质增生，免疫荧光以C3沉积为主，电镜下3例诊断为C3肾小球肾炎（C3GN），1例为致密沉积病（DDD）；3例患儿行全外显子组测序，仅1例检出C3基因c.4887G>C（p.Glu1629Asp）错义变异，遗传自表型健康母亲，ACMG 评级为临床意义不明确。所有患儿均接受糖皮质激素联合免疫抑制剂治疗，其中2例加用依库珠单抗。随访时间3~8个月，3例初始肾功能不全患儿均恢复正常，4例尿蛋白均有降低，2例达到完全缓解，1例部分缓解，1例未缓解。结论 儿童C3G以肾病综合征为主要表现，常伴持续低补体C3血症，病理以弥漫性系膜增生、C3为主沉积为特征，基因变异检出率较低；糖皮质激素联合免疫抑制剂为常用治疗方案，部分难治性病例加用依库珠单抗可获得一定疗效，早期肾活检联合补体检测、基因分析有助于精准诊治，长期预后需进一步延长随访观察。

Objective To investigate the clinical phenotypes, pathological characteristics, genetic variants, and treatment outcomes in children with C3 glomerulopathy (C3G), and to provide evidence for precise diagnosis and management. Methods Clinical, pathological, and genetic data from four pediatric patients diagnosed with C3G at the Department of Nephrology between July 2021 and March 2024 were retrospectively analyzed. Additionally, published cases of C3G in Chinese children from both domestic and international literature were systematically reviewed and summarized to contextualize our findings. Results Four pediatric patients with C3G were included in the study, comprising two boys and two girls aged 10 to 12 years. All presented with nephrotic syndrome and hematuria, and three exhibited renal insufficiency at initial presentation. Laboratory evaluation revealed reduced serum complement C3 levels (0.9-1.8 g/L) in all patients, decreased C4 in two, and elevated membrane attack complex (C5b-9) in all. Renal histopathology demonstrated diffuse mesangial cell and matrix proliferation in all cases. Immunofluorescence showed predominant C3 deposition, and electron microscopy confirmed a diagnosis of C3 glomerulonephritis (C3GN) in three patients and dense deposit disease (DDD) in one. Whole exome sequencing was performed in three patients, identifying a single missense variant in the C3 gene (c.4887G>C, p.Glu1629Asp) inherited from a phenotypically healthy mother; this variant was classified as having uncertain clinical significance according to ACMG criteria. All patients received immunosuppressive therapy combining glucocorticoids with other agents; eculizumab was added in two refractory cases. With follow-up of 3 to 8 months, all three patients with initial renal insufficiency achieved normalization of renal function, and proteinuria decreased in all four. Two patients attained complete remission, one achieved partial remission, and one showed no response. Conclusions Pediatric C3G predominantly manifests as nephrotic syndrome with persistent hypocomplementemia. Key pathological features include diffuse mesangial proliferation and dominant C3 deposition on immunofluorescence. Genetic variants are infrequently detected, suggesting potential non-monogenic mechanisms in many cases. Immunosuppressive regimens based on glucocorticoids remain the mainstay of therapy, while eculizumab may offer therapeutic benefit in selected refractory cases. Early integration of renal biopsy, complement profiling, and genetic analysis facilitates timely and accurate diagnosis. Long-term outcomes require further assessment through extended follow-up and larger cohort studies.