ORIGINAL ARTICLE IgA nephropathy with presentation of nephrotic syndrome at onset in children Yuko Shima 1 & Koichi Nakanishi 1 & Masashi Sato 1 & Taketsugu Hama 1 & Hironobu Mukaiyama 1 & Hiroko Togawa 1 & Ryojiro Tanaka 2 & Kandai Nozu 3 & Mayumi Sako 4 & Kazumoto Iijima 3 & Hiroyuki Suzuki 1 & Norishige Yoshikawa 5 Received: 21 July 2016 /Revised: 2 September 2016 /Accepted: 6 September 2016 # IPNA 2016 Abstract Background Despite a low incidence, nephrotic syndrome (NS) can present with IgA nephropathy (IgAN). The clinical characteristics and long-term outcomes of pediatric patients with IgAN presenting with NS (NS-IgAN) at onset have not been fully elucidated. Methods We retrospectively analyzed 426 patients, and com- pared clinical and pathological (Oxford) findings between those with NS-IgAN and those with non-NS-IgAN. Results Among 426 patients, 30 (7.0 %) had NS-IgAN. Logistic analyses showed that male sex (OR: 7.6, p = 0.0002), M1 (OR: 10.3, p = 0.002), and E1 (OR: 15.2, p = 0.0001) were significantly related to NS. The mean obser- vation period was 6.2 ± 3.2 years. Although NS-IgAN was associated with significantly lower renal survival than non- NS-IgAN according to Kaplan–Meier analysis (p = 0.02), re- nal survival of NS-IgAN was good (92.4 % at 10 years). The most significant prognostic factor for renal survival was re- mission of proteinuria after treatment, and NS at onset is also a significant prognostic factor for renal survival after adjusting for remission of proteinuria. Twenty children with NS-IgAN were treated with prednisolone alone, or prednisolone and immunosuppressant. Remission of proteinuria occurred in 21 patients. Three cases of NS-IgAN progressed to stage III–V chronic kidney disease at the most recent observation. They all demonstrated heavy proteinuria after the 2-year initial treatment. The significant factor for persistent proteinuria at 5 years was S1 in NS-IgAN. Conclusions The most significant factor for renal survival was responsiveness to treatment, not NS itself. As modifiable acute lesions are the dominant pathological findings in NS- IgAN, histological improvements achieved by appropriate treatments can result in a favorable prognosis. Keywords IgA nephropathy . Nephrotic syndrome . End-stage renal disease . Remission of proteinuria Introduction IgA nephropathy (IgAN) is the most common form of glomer- ulonephritis worldwide. It is the main cause of end-stage renal disease (ESRD) in patients of all ages with primary glomerular disease [1, 2]. A study of 241 Japanese pediatric patients with IgAN revealed that 11 % of patients developed ESRD within 15 years [3]. Poor prognostic factors of childhood IgAN at diagnosis include heavy proteinuria and severe pathological changes such as diffuse mesangial proliferation (DMP) [4]. Conversely, patients with mild proteinuria or mild pathologi- cal changes sometimes enter spontaneous remission without treatment [5]. Patients with IgAN can present with nephrotic syndrome (NS), although the incidence is low. The clinical Part of this study was presented at the 48th Annual Meeting of the American Society of Nephrology, San Diego, USA, 2015 * Koichi Nakanishi knakanis@wakayama-med.ac.jp 1 Department of Pediatrics, Wakayama Medical University, 811-1 Kimiidera, Wakayama City, Wakayama 641-8509, Japan 2 Department of Nephrology, Hyogo Prefectural Kobe Children’ s Hospital, Kobe, Hyogo, Japan 3 Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan 4 Division for Clinical Trials, Center for Clinical Research and Development, National Center for Child Health and Development, Tokyo, Japan 5 Clinical Research Center, Wakayama Medical University, Wakayama City, Wakayama, Japan Pediatr Nephrol DOI 10.1007/s00467-016-3502-6