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Focal segmental glomerular sclerosis (FSGS) is 1 of the primary causes of nephrotic syndrome in both pediatric and adult patients, which can lead to end-stage kidney disease. Recurrence of FSGS after kidney transplantation significantly increases allograft loss, leading to morbidity and mortality. Currently, there are no consensus guidelines for identifying those patients who are at risk for recurrence or for the management of recurrent FSGS. Our work group performed a literature search on PubMed/Medline, Embase, and Cochrane, and recommendations were proposed and graded for strength of evidence. Of the 614 initially identified studies, 221 were found suitable to formulate consensus guidelines for recurrent FSGS. These guidelines focus on the definition, epidemiology, risk factors, pathogenesis, and management of recurrent FSGS. We conclude that additional studies are required to strengthen the recommendations proposed in this review., (Copyright © 2023 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Idiopathic nephrotic syndrome is the most frequent pediatric glomerular disease, affecting from 1.15 to 16.9 per 100,000 children per year globally. It is characterized by massive proteinuria, hypoalbuminemia, and/or concomitant edema. Approximately 85-90% of patients attain complete remission of proteinuria within 4-6 weeks of treatment with glucocorticoids, and therefore, have steroid-sensitive nephrotic syndrome (SSNS). Among those patients who are steroid sensitive, 70-80% will have at least one relapse during follow-up, and up to 50% of these patients will experience frequent relapses or become dependent on glucocorticoids to maintain remission. The dose and duration of steroid treatment to prolong time between relapses remains a subject of much debate, and patients continue to experience a high prevalence of steroid-related morbidity. Various steroid-sparing immunosuppressive drugs have been used in clinical practice; however, there is marked practice variation in the selection of these drugs and timing of their introduction during the course of the disease. Therefore, international evidence-based clinical practice recommendations (CPRs) are needed to guide clinical practice and reduce practice variation. The International Pediatric Nephrology Association (IPNA) convened a team of experts including pediatric nephrologists, an adult nephrologist, and a patient representative to develop comprehensive CPRs on the diagnosis and management of SSNS in children. After performing a systematic literature review on 12 clinically relevant PICO (Patient or Population covered, Intervention, Comparator, Outcome) questions, recommendations were formulated and formally graded at several virtual consensus meetings. New definitions for treatment outcomes to help guide change of therapy and recommendations for important research questions are given., (© 2022. The Author(s).)

Objectives: To present our experience of treating steroid-dependent nephrotic syndrome (SDNS) in children with repeated doses of rituximab (RTX) with a relatively long follow-up, and to discuss the role of the histopathology type and previous immune-suppressor (IS) drugs on the outcome of these patients., Methods: The patients included in this prospective study were children with SDNS who were in remission on a high-dose steroid or with additional IS drugs. All patients underwent renal biopsy before RTX treatment. Intravenous RTX was administered monthly at 375 mg/m 2 for 4 doses. Response to treatment was defined as maintaining remission with no steroid-sparing agents or prednisone for one year., Results: Seventeen (14 males) patients were enrolled. Approximately 76% had minimal change disease (MCD) and 3 (18%) patients had immunoglobulin M (IgM) nephropathy. Approximately 85% of MCD and 33% of IgM nephropathy showed complete response to RTX., Conclusion: Compared to other IS used to treat SDNS, RTX showed a significant decrease in relapse rate with fewer side effects. The dose and interval should be modified according to the patient's characteristics, such as medical history, pathology type, and previous IS agents., (Copyright: © Saudi Medical Journal.)

Background: Nephrotic syndrome is the most common kidney disease in children worldwide. Our aim was to critically appraise the quality of recent Clinical Practice Guidelines (CPGs) for idiopathic steroid-sensitive nephrotic syndrome (SSNS) in children in addition to summarize and compare their recommendations., Methods: Systematic review of CPGs. We identified clinical questions and eligibility criteria and searched and screened for CPGs using bibliographic and CPG databases. Each included CPG was assessed by four independent appraisers using the Appraisal of Guidelines for REsearch & Evaluation II (AGREE-II) instrument. We summarized the recommendations in a comparison practical table., Results: Our search retrieved 282 citations, of which three CPGs were eligible and appraised: Kidney Disease: Improving Global Outcomes (KDIGO) 2012, Japan Society for Pediatric Nephrology (JSPN) 2014, and American Academy of Pediatrics (AAP) 2009. Among these, the overall assessment of two evidence-based CPGs scored > 70% (KDIGO and JSPN), which was consistent with their higher scores in the six domains of the AGREE II Instrument. In domain 3 (rigor of development), KDIGO, JSPN, and AAP scored 84%, 74%, and 41%, respectively. In domain 5 (applicability), they scored 22%, 16%, and 19%, respectively, and in domain 6 (editorial independence), they scored 94%, 65%, and 88%, respectively., Conclusions: The methodological quality of the KDIGO CPG was superior, followed by JSPN and AAP CPGs with the relevant recommendations for use in practice., Systematic Review Registration: The protocol was registered in the Center for Open Science (OSF) DOI: 10.17605/OSF.IO/6QTMD and in the International prospective register of systematic reviews PROSPERO 2020 CRD42020197511 .

Background: Approximately 50% of children with steroid-sensitive nephrotic syndrome (SSNS) will suffer from frequent relapses or steroid dependency, prompting the use of so-called steroid-sparing drugs. In this pilot study, we compare the efficacy and safety of rituximab to oral cyclophosphamide as first-line steroid-sparing medications., Methods: A prospective open-label non-randomized study of children with frequent relapsing or steroid-dependant SSNS. Exclusion criteria were steroid-resistant disease, prescription of immunosuppressive agents other than prednisolone or levamisole, evidence of impaired kidney function, leucopenia, or active infection. The recruited children were allocated either to the oral cyclophosphamide (3 mg/kg/day for 8 weeks) or intravenous rituximab treatment (two doses of 375 mg/m 2 /dose, 2 weeks apart) and were monitored for relapses and side effects for 12 months., Results: Forty-six subjects were included from two centers; 27 received cyclophosphamide and 19 received rituximab. One-year relapse-free survival was reached in 17 (58.6%) patients treated with cyclophosphamide compared to 16 (84.2%) with rituximab (adjusted HR 0.36; 95% CI 0.09-1.45; p = 0.151). The mean interval to relapse was 6.9 months in the cyclophosphamide group (N = 10) and 6.3 months in the rituximab group (N = 3). Both treatments were associated with a significant (p < 0.001) reduction in prescribed dose of oral alternate-day steroid from 1.02 to 0.36 mg/kg (cyclophosphamide) and 0.86 to 0.08 mg/kg (rituximab). Importantly, a significantly (p = 0.003) higher percentage of patients achieved complete withdrawal of steroid within 3 months of commencing study treatment in the rituximab (73.7%) versus cyclophosphamide (29.6%) group. Transient leucopenia was the most frequent adverse effect observed in the cyclophosphamide group (18.5%) and one patient (3.4%) had acute hepatotoxicity besides severe leucopenia and neutropenia in the 7th week of treatment with complete recovery with the withdrawal of cyclophosphamide and maintenance of remission. A minor infusion-related reaction in the form of a generalized macular skin rash was observed in one patient (5%) in the rituximab group., Conclusions: Rituximab is non-inferior to cyclophosphamide and safe as a first-line steroid-sparing agent in children with SSNS. A larger multicenter study is required to assess superiority over cyclophosphamide. Graphical abstract.

Background: Congenital and infantile nephrotic syndrome (CNS and INS) are rare inherited defects in glomerular filtration involving a variety of gene mutations. This study aimed to analyze all genetic mutations associated with congenital and infantile nephrotic syndrome treated at our institution. We also discussed our different approach secondary to culture and resources., Methods: A retrospective single-center study of all children diagnosed as NS before the age of 1 year over a duration of over one decade., Results: Twenty-nine children (12 boys) were included in the study. Their median age (range) was 2.4 (0.1-12) months (20 CNS and 9 INS). Consanguinity was present in 90% of children. The genetic analysis' results were only available for 20 children. An underlying causative homozygous mutation was detected in 18 children (90%): NPHS1 (9), NPHS2(2), LAMB2(3), PLCE1(1), WT1(1), and ITSN1 novel mutation (2). One child had heterozygous mutation of NPHS2 and another child had heterozygous mutation of NPHS1 which could not explain the disease. All CNS cases were all managed with intermittent intravenous albumin infusion, ACEi, diuretics, and indomethacin. None of the children were managed by nephrectomy followed by peritoneal dialysis (PD) because of limited resources. Only one child achieved partial remission, while 15 children died at a median (range) age of 5.8 (1.25-29) months. The remaining 14 children were followed up for an average of 36 (3.9-120) months. Three children progressed to end-stage kidney disease and PD was performed in only two children., Conclusions: NPHS1 is the main underlying cause of CNS and INS in our study population. CNS and INS were associated with high morbidity and mortality.

Steroid-resistant nephrotic syndrome (SRNS) almost invariably progresses to end-stage renal disease. Although more than 50 monogenic causes of SRNS have been described, a large proportion of SRNS remains unexplained. Recently, it was discovered that mutations of NUP93 and NUP205, encoding 2 proteins of the inner ring subunit of the nuclear pore complex (NPC), cause SRNS. Here, we describe mutations in genes encoding 4 components of the outer rings of the NPC, namely NUP107, NUP85, NUP133, and NUP160, in 13 families with SRNS. Using coimmunoprecipitation experiments, we showed that certain pathogenic alleles weakened the interaction between neighboring NPC subunits. We demonstrated that morpholino knockdown of nup107, nup85, or nup133 in Xenopus disrupted glomerulogenesis. Re-expression of WT mRNA, but not of mRNA reflecting mutations from SRNS patients, mitigated this phenotype. We furthermore found that CRISPR/Cas9 knockout of NUP107, NUP85, or NUP133 in podocytes activated Cdc42, an important effector of SRNS pathogenesis. CRISPR/Cas9 knockout of nup107 or nup85 in zebrafish caused developmental anomalies and early lethality. In contrast, an in-frame mutation of nup107 did not affect survival, thus mimicking the allelic effects seen in humans. In conclusion, we discovered here that mutations in 4 genes encoding components of the outer ring subunits of the NPC cause SRNS and thereby provide further evidence that specific hypomorphic mutations in these essential genes cause a distinct, organ-specific phenotype.

Nephrotic syndrome (NS) is a renal disease characterized by heavy proteinuria, hypoalbuminemia, edema and hyperlipidemia. Its presentation within the first 3 months of life or in multiple family members suggests an underlying inherited cause. To determine the frequency of inherited NS, 62 cases (representing 49 families with NS) from Saudi Arabia were screened for mutations in NPHS1, NPHS2, LAMB2, PLCE1, CD2AP, MYO1E, WT1, PTPRO and Nei endonuclease VIII-like 1 (NEIL1). We detected likely causative mutations in 25 out of 49 families studied (51%). We found that the most common genetic cause of NS in our cohort was a homozygous mutation in the NPHS2 gene, found in 11 of the 49 families (22%). Mutations in the NPHS1 and PLCE1 genes allowed a molecular genetic diagnosis in 12% and 8% of families, respectively. We detected novel MYO1E mutations in three families (6%). No mutations were found in WT1, PTPRO or NEIL1. The pathogenicity of novel variants was analyzed by in silico tests and by genetic screening of ethnically matched control populations. This is the first report describing the molecular genetics of NS in the Arabian Peninsula.

BackgroundSphingosine-1-phosphate lyase insufficiency syndrome (SPLIS) is a recently recognized inborn error of metabolism associated with steroid-resistant nephrotic syndrome as well as adrenal insufficiency and immunological, neurological, and skin manifestations. SPLIS is caused by inactivating mutations in SGPL1, encoding the pyridoxal 5'phosphate-dependent enzyme sphingosine-1-phosphate lyase, which catalyzes the final step of sphingolipid metabolism. Some SPLIS patients have undergone kidney transplantation, and others have been treated with vitamin B6 supplementation. In addition, targeted therapies including gene therapy are in preclinical development. In anticipation of clinical trials, it will be essential to characterize the full spectrum and natural history of SPLIS. We performed a retrospective analysis of 76 patients in whom the diagnosis of SPLIS was established in a proband with at least one suggestive finding and biallelic SGPL1 variants identified by molecular genetic testing. The main objective of the study was to identify factors influencing survival in SPLIS subjects.ResultsOverall survival at last report was 50%. Major influences on survival included: (1) age and organ involvement at first presentation; (2) receiving a kidney transplant, and (3) SGPL1 genotype. Among 48 SPLIS patients with nephropathy who had not received a kidney transplant, two clinical subgroups were distinguished. Of children diagnosed with SPLIS nephropathy before age one (n = 30), less than 30% were alive 2 years after diagnosis, and 17% were living at last report. Among those diagnosed at or after age one (n = 18), ~ 70% were alive 2 years after diagnosis, and 72% were living at time of last report. SPLIS patients homozygous for the SPL R222Q variant survived longer compared to patients with other genotypes. Kidney transplantation significantly extended survival outcomes.ConclusionOur results demonstrate that SPLIS is a phenotypically heterogeneous condition. We find that patients diagnosed with SPLIS nephropathy in the first year of life and patients presenting with prenatal findings represent two high-risk subgroups, whereas patients harboring the R222Q SGPL1 variant fare better than the rest. Time to progression from onset of proteinuria to end stage kidney disease varies from less than one month to five years, and kidney transplantation may be lifesaving.

Background: This study aimed to determine the prevalence and etiology of kidney failure (KF) among children below 15 years of age receiving chronic dialysis in Saudi Arabia and describe their dialysis modalities. Methods: This cross-sectional descriptive study was conducted on 8 August 2022, encompassing all 23 pediatric dialysis centers in Saudi Arabia. Data gathered comprised patient demographics, causes of KF, and the dialysis methods employed. Collected data underwent analysis to determine prevalence of children undergoing chronic dialysis, discern underlying causes of KF, and evaluate distribution of patients across different dialysis modalities. Results: The prevalence of children on chronic dialysis is 77.6 per million children living in Saudi Arabia, equating to 419 children. The predominant underlying cause of KF was congenital anomalies of the kidneys and urinary tract (CAKUT), representing a substantial 41% of cases. Following this, others or unknown etiologies accounted for a noteworthy 25% of cases, with focal segmental glomerulosclerosis (FSGS) comprising 13%, glomerulonephritis at 11%, and congenital nephrotic syndrome contributing 10% to etiological distribution. Regarding dialysis modalities employed, 67% of patients were on peritoneal dialysis (PD), while the remaining 33% were on hemodialysis (HD). Conclusions: This first nationwide study of pediatric chronic dialysis in Saudi Arabia sheds light on the prevalence of children undergoing chronic dialysis and underlying causes of their KF, thereby contributing to our understanding of clinical management considerations. This research serves as a stepping stone for the development of national registries. [ABSTRACT FROM AUTHOR]

Galloway-Mowat syndrome is a rare autosomal recessive disease characterized by a unique combination of renal and neurological manifestations, including early-onset steroid-resistant nephrotic syndrome, microcephaly, psychomotor delay, and gyral abnormalities of the brain. Most patients die during early childhood. Here, we identified a novel homozygous O-sialoglycoprotein endopeptidase (OSGEP) variant, NM_017807.3:c.973C>G (p.Arg325Gly), in four affected individuals in an extended consanguineous family from Saudi Arabia. We have described the detailed clinical characterization, brain imaging results, and muscle biopsy findings. The described phenotype varied from embryonic lethality to early pregnancy loss or death at the age of 9. Renal disease is often the cause of death. Protein modeling of this OSGEP variant confirmed its pathogenicity. In addition, proteomic analysis of the affected patients proposed a link between the KEOPS complex function and human pathology and suggested potential pathogenic mechanisms. [ABSTRACT FROM AUTHOR]

Objectives: To identify the trends in the diagnostic frequency of glomerular disease subtypes by renal biopsy in children in Saudi Arabia over the last 20 years. Methods: In this retrospective observational study, we identified all patients aged <18 years for whom native kidney biopsy was performed between 1998 and 2017. The period during which biopsy was performed (1998-2004, 2005-2011, and 2012-2017) and the demographic information and their association with the prevalence of various glomerular disease subtypes were our primary outcomes. Results: A total of 326 cases with renal biopsy were analyzed; the mean age of participants being 11 years and 45.4% of them were girls. Unexpectedly, secondary glomerulonephritis accounted for 42.3% of the cases, and lupus nephritis was the most common cause noted in 20.7% of the cases. The minimal change and focal segmental glomerulosclerosis were the most common glomerulonephritis in 59% of the cases. The frequency of membranoproliferative glomerulonephritis and mesangioproliferative glomerulonephritis significantly decreased from 15% and 17% in the period prior to 2004 to 3.3% (p=0.003) and 1.7% in 2012-2017 (p<0.001). Conclusions: We found a considerable shift in the frequency of many glomerular disease subtypes in 1998-2017, which make clinical predication of the underlying etiology challenging for clinician. Renal biopsy still remains a critical diagnostic procedure for managing a considerable proportion of renal diseases. [ABSTRACT FROM AUTHOR]