目的　探讨由毛细血管内增生性肾小球肾炎(EnPGN)转为膜增生性肾小球肾炎(MPGN)的发病机制、诊断要点及治疗。方法　回顾性分析1例肾脏病理由EnPGN转为MPGN患儿的临床资料及肾活检病理结果。结果　患儿临床表现为蛋白尿及镜下血尿，持续性低补体C3血症，病理类型由EnPGN转为MPGN，经口服激素联合他克莫司治疗后，尿蛋白转阴，补体C3仍低。结论　持续补体C3降低的患儿，病理类型可转变，需要早期诊断及时治疗。

Objective　To investigate the mechanism, diagnosis and treatment of membrane proliferative glome-rulonephritis (MPGN) transitioned from endocapillary proliferative glomerulonephritis (EnPGN). Methods  The clinical data and the results of pathological examination of one case of MPGN transitioned from EnPGN were retrospectively analyzed. Results The child was presented with proteinuria, microscopic hematuria, and persistent low level of complement C3. The type of renal pathology was transitioned from EnPGN to MPGN. Complete remission was achieved in this child with the treatment of oral prednisolone and tacrolimus, but the level of plasma complement C3 remained low. Conclusions  The type of renal pathology in children with persistent low level of complement C3 could make a transition, and the early diagnosis, timely and effective treatment are important.