Nagano C, Hara S, Yoshikawa N, Takeda A, Gotoh Y, Hamada R, Matsuoka K, Yamamoto M, Fujinaga S, Sakuraya K, Kamei K, Hamasaki Y, Oguchi H, Araki Y, Ogawa Y, Okamoto T, Ito S, Tanaka S, Kaito H, Aoto Y, Ishiko S, Rossanti R, Sakakibara N, Horinouchi T, Yamamura T, Nagase H, Iijima K, and Nozu K
Background: Approximately 30% of children with steroid-resistant nephrotic syndrome (SRNS) have causative monogenic variants. SRNS represents glomerular disease resulting from various etiologies, which lead to similar patterns of glomerular damage. Patients with SRNS mainly exhibit focal segmental glomerulosclerosis (FSGS). There is limited information regarding associations between histologic variants of FSGS (diagnosed using on the Columbia classification) and monogenic variant detection rates or clinical characteristics. Here, we report FSGS characteristics in a large population of affected patients., Methods: This retrospective study included 119 patients with FSGS, diagnosed using the Columbia classification; all had been referred to our hospital for genetic testing from 2016 to 2021. We conducted comprehensive gene screening of all patients using a targeted next-generation sequencing panel that included 62 podocyte-related genes. Data regarding patients' clinical characteristics and pathologic findings were obtained from referring clinicians. We analyzed the associations of histologic variants with clinical characteristics, kidney survival, and gene variant detection rates., Results: The distribution of histologic variants according to the Columbia classification was 45% ( n =53) FSGS not otherwise specified, 21% ( n =25) cellular, 15% ( n =18) perihilar, 13% ( n =16) collapsing, and 6% ( n =7) tip. The median age at end stage kidney disease onset was 37 years; there were no differences in onset age among variants. We detected monogenic disease-causing variants involving 12 of the screened podocyte-related genes in 34% (40 of 119) of patients. The most common genes were WT1 (23%), INF2 (20%), TRPC6 (20%), and ACTN4 (10%). The perihilar and tip variants had the strongest and weakest associations with detection of monogenic variants (83% and 0%, respectively; P <0.001)., Conclusions: We revealed the distributions of histologic variants of genetic FSGS and nongenetic FSGS in a large patient population. Detailed data concerning gene variants and pathologic findings are important for understanding the etiology of FSGS., Competing Interests: R. Hamada reports research funding from Chugai Pharmaceutical Co., Ltd., Kyowa Kirin Co., Ltd., Takeda Pharmaceutical Co., and Teijin Pharma Ltd.; and honoraria from Alexion Pharmaceuticals, Inc., Asahi Kasei Pharma Corporation, Chugai Pharmaceutical Co., Ltd., and Teijin Pharma Ltd. T. Horinouchi reports research funding from Otsuka Pharmaceutical Co., Ltd. K. Iijima reports consultancy for JCR Pharmaceuticals Co., Ltd., Kyowa Hakko Kirin Co., Ltd., Ono Pharmaceutical Co., Ltd., Sanofi K.K., Takeda Pharmaceutical Co., Ltd., and Zenyaku Kogyo Co., Ltd.; research funding from Air Water Medical, Inc., Astellas Pharma, Inc., Eisai Co., Ltd., JCR Pharmaceutical Co., Ltd., Mochida Pharmaceutical Co., Ltd., Nihon Pharmaceutical Co., Ltd., Otsuka Pharmaceutical Co., Ltd., Shionogi & Co., Ltd., and Zenyaku Kogyo Co., Ltd.; honoraria from Astellas Pharma, Inc., Chugai Pharmaceutical Co., Ltd., Integrated Development Associates Co., Ltd., Kyowa Hakko Kirin Co., Ltd., Shionogi & Co., Ltd., and Zenyaku Kogyo Co., Ltd.; a patent application on the development of antisense nucleotides for exon skipping therapy in Alport syndrome; and an advisory or leadership role for CJASN and Pediatric Nephrology (Editorial Board). S. Ito reports consultancy for Alexion Pharma, Takeda Pharmaceutical Company, Teijin Pharma, and Zenyaku Kogyo Co Ltd.; research funding from Asahi Kasei Pharma, Chugai Pharmaceutical Co., Ltd., CSL Behring, Kyowa Hakko Kirin Co., Ltd., Maruho Pharma, Mitsubishi Tanabe Pharma, and Teijin Pharma Ltd.; honoraria from Alexion Pharma, Teijin Pharma Ltd., and Zenyaku Kogyo Co., Ltd.; an advisory or leadership role for Clinical Experimental Nephrology, JMA Journal, and the Korean Journal of Pediatrics; and participation in a speakers’ bureau for AbbVie LLC, Alexion Pharma, Asahi Kasei Pharma, Astellas Pharma, Inc., Chugai Pharmaceutical Co., Ltd., CSL Behring, Daiichi Sankyo Co., Ltd., Mitsubishi Tanabe Pharma, Novartis Pharma K.K., Pfizer Japan, Inc., Sanofi Co., Ltd., Teijin Pharma Ltd., and Zenyaku Kogyo Co., Ltd. K. Kamei reports research funding from Astellas Pharma, Inc., Chugai Pharmaceutical Co., Ltd., Public Foundation of Vaccination Research Center, Taiju Life Social Welfare Foundation, Terumo Foundation for Life Sciences and Arts, Ono Pharmaceutical Co; Otsuka Pharmaceutical Co., Ltd., Teijin Pharma Ltd; Shionogi Co., Ltd.; and honoraria from Baxter Ltd., Tanabe Mitsubishi Pharma, and Zenyaku Kogyo Co., Ltd. K. Matsuoka reports participating in a speakers’ bureau for Chugai Pharmaceutical Co., Ltd. K. Nozu reports research funding from Chugai Pharmaceutical Company, Dainippon Sumitomo Pharmaceutical Company, Kyowa Kirin Pharmaceutical Company, and Shionogi, Inc.; patents or royalties from Daiichi Sankyo Pharmaceutical Company; an advisory or leadership role for Kyowa Kirin Pharmaceutical Company and Toa Eiyo Ltd.; and receiving lecture fees from Chugai Pharmaceutical Company, Chugai Pharmaceutical Co., Ltd., Daiichi Sankyo Company, Ltd., Kyowa Kirin Pharmaceutical Company, Novartis Pharma Co., Ltd., and Sumitomo Dainippon Pharma Co., Ltd. All remaining authors have nothing to disclose., (Copyright © 2022 by the American Society of Nephrology.)