Kidney Transplant Outcomes in Pediatric Nephronophthisis in a Single Japanese Center

Background and Purpose: Nephronophthisis (NPH) is a hereditary disease that progresses to end-stage kidney disease at a relatively young age. However, reports on NPH, including outcomes after kidney replacement therapy (KRT), remain limited. We investigated diagnostic triggers, age at detection, extrarenal complications, genetic mutations, KRT, growth, and graft outcome in patients with NPH. Methods: We retrospectively reviewed the medical records of 14 patients with NPH who underwent kidney transplantation (KTx) in our center between 2009 and 2024. This study included 9 (64.3%) males and 5 (35.7%) females. The median age at transplantation was 8.8 years. Results: The most common diagnostic triggers were thoracic hypoplasia, school health checkups, and incidental testing. Extrarenal complications were observed in 9 (64.3%) patients. Among 10 patients who underwent genetic testing, NPH-related gene mutations were identified in 7 (70.0%) patients. Kidney function was well maintained after KTx. The median height standard deviation score (SDS) at transplantation was −2.0. Conclusions: Extrarenal manifestations appear to be useful in the diagnosis of NPH. Although kidney function is well preserved after KTx, improvement of height at transplantation remains an important challenge for catch-up growth.