#844 Renal manifestations of immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome: an updated systematic review

Abstract Background and Aims Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a systemic autoimmune genetic disorder caused by mutation of the forkhead box protein 3 (FOXP3) gene. We performed this study to analyze the clinical and demographic characteristics of renal involvement in IPEX patients, genotype-phenotype correlations and the effect of renal involvement on patient outcome. Method We performed a literature search (PubMed and EMBASE) to systematically investigate the case reports of IPEX with renal involvement which were published before Dec 21st, 2023. Results A total of 37 patients were identified. All IPEX patients included had FOXP3 mutations which were most frequently located in the forkhead domain. Among 25 patients in whom detailed information is available, 22 showed single presentation (6 proteinuria, 8 nephrotic syndrome (nephrotic range proteinuria), 3 acute glomerulonephritis, 5 renal insufficiency), 2 showed multiple presentations (1 nephrotic range proteinuria, microscopic hematuria and 1 nephrotic range proteinuria, microscopic hematuria, renal insufficiency). Renal biopsy was documented in 19 patients. Membranous nephropathy (n = 9) was most common, followed by Interstitial nephritis (n = 3), membranoproliferative nephropathy (n = 2), tubulopathy (n = 2), mesangial proliferative glomerulonephritis (n = 2), autoimmune nephritis (n = 1). Nephrotic syndrome was more frequent in patients with intron 6 mutation (p 0.05). However, renal presentation of IPEX syndrome was not related to patient outcome (death). Conclusion We found renal involvement is one of the important manifestations of IPEX syndrome and membranous nephropathy was most common. Close renal monitoring is necessary to detect renal involvement of IPEX syndrome. Further studies are necessary to compare the course of glomerulonephritis between IPEX-related and IPEX-unrelated one. Response to treatment should also be elucidated in patients with IPEX in the future.