Outcome of children with IgA vasculitis with nephritis treated with steroids: a matched controlled study.

BACKGROUND: IgA vasculitis (IgAV) is the most common vasculitis in children. IgAV long-term prognosis depends on kidney involvement or IgA vasculitis with nephritis (IgAVN). To date, steroid treatment (oral steroids or methylprednisolone pulses) has not proven to be formally efficient. This study aimed to assess the role of steroids on IgAVN outcome. METHODS: All children with IgAVN diagnosed 2000-2019 in 14 French pediatric nephrology units with minimal follow-up of 6 months were retrospectively included. Outcomes of patients treated with steroids were compared with those of a control group of untreated patients matched for age, sex, proteinuria, eGFR, and histological features. The primary endpoint was IgAVN remission defined as urine protein-to-creatinine ratio < 20 mg/mmol without impaired eGFR one year after disease onset. RESULTS: A total of 359 patients with IgAVN were included with a median follow-up time of 249 days (range 43-809). One hundred eight (30%) patients received oral steroids alone, 207 (51%) patients received three methylprednisolone pulses followed by oral steroids, and 44 patients (12.5%) did not receive steroids. Thirty-two children treated with oral steroids alone were compared with 32 matched control patients who did not receive steroids. One year after disease onset, IgAVN remission proportion was not different between these two groups: 62% versus 68%, respectively. Ninety-three children treated with oral steroids alone were compared with 93 matched patients treated with three methylprednisolone pulses followed by oral corticosteroids. IgAVN remission proportion was not different between these two groups: 77% versus 73%, respectively. CONCLUSION: The benefit of oral steroids alone and methylprednisolone pulses could not be established based on this observational study. Randomized controlled trials are thus required to determine the efficacy of steroids in IgAVN. A higher resolution version of the Graphical abstract is available as Supplementary information.

Impact of nephrology care trajectories pre-CKD stage 5 on initiation of kidney replacement therapy in children.

BACKGROUND: To improve pre-emptive kidney transplantation (PKT) in children and limit starting dialysis in an emergency, we aimed to describe nephrology care trajectories pre-CKD stage 5. METHODS: We included all children in France who, between 2010 and 2016, started kidney replacement therapy (KRT): standard dialysis (reference group) and emergency dialysis or PKT. We identified four pre-CKD stage 5 nephrology care trajectories before KRT that were extracted from the national exhaustive medical-administrative database and used logistic regression to explore associations between patient characteristics, care trajectories, and KRT initiation. RESULTS: Six hundred forty-three pediatric patients started KRT in France; 406 started dialysis and 30.5% emergency dialysis. The "optimal" care trajectory encompassed 179 patients, 82.7% with at least 18 months nephrology follow-up. Conversely, the "no care" trajectory encompassed 118 patients with no nephrology follow-up before KRT. The "severe" trajectory encompassed 128 patients; 93% hospitalized more than once a year and 18% in an intensive care unit. Finally, the "irregular" trajectory encompassed 127 patients, 77% and 46% with irregular laboratory monitoring and CKD drug delivery, respectively. With the "optimal" trajectory as the reference, probability of emergency dialysis was higher with the "irregular" and "no care" trajectories (odds ratio 3.02 [95% confidence interval 1.18-7.66] and 26.5 [10.8-64.8], respectively), and PKT was reduced with the "severe" trajectory (0.43 [0.23-0.82]). CONCLUSION: We identified a group of patients with irregular follow-up who may benefit the most from interventions aiming at improving adherence to treatment and earlier diagnosis of their CKD to improve access to PKT. A higher resolution version of the Graphical abstract is available as Supplementary information.

Setting reasonable objectives for improving preemptive kidney transplantation rates in children.

BACKGROUND: This study aims to develop a method to estimate the potential of preemptive kidney transplantation (PKT) by identifying patients who were transplanted after a dialysis period (non-preemptive kidney transplantation (NPKT)) despite being medically suitable for PKT. METHODS: All children (< 18 years old) starting kidney replacement therapy (KRT) in France, between 2010 and 2016 and transplanted before December 31, 2017, were included. A propensity score (PS) of receiving PKT was estimated by multivariate logistic regression based on recipient medical characteristics. Healthcare use during the 24 months prior to KRT initiation was extracted from the French National Health Insurance database, and a pre-KRT follow-up of more than 18 months was considered sufficient to allow preemptive transplantation. RESULTS: Among 643 patients who started KRT, 149 (23.2%) were preemptively transplanted. Using PS stratification, among 391 NPKT patients, we identified 145 patients (37%) suitable for PKT, according to clinical characteristics. Mean age was 12.3 years, 67% were males, and 56% had urological abnormalities. Among those 145 patients, we identified 79 NPKT patients who started on dialysis despite early referral to a nephrologist (more than 18 months prior to KRT initiation). CONCLUSIONS: This method estimates a potential of 228 (149 + 79) PKT (35%) among pediatric patients in France. A similar method could be used in adults or in other countries. Estimation of the rate of patients with CKD stage 5 medically suitable for PKT will be of interest for health policy makers when setting up objectives for improvement in preemptive kidney transplant access.

Towards adulthood with a solitary kidney.

Around 1/1000 people have a solitary kidney. Congenital conditions mainly include multicystic dysplastic kidney and unilateral renal aplasia/agenesis; acquired conditions are secondary to nephrectomy performed because of urologic structural abnormalities, severe parenchymal infection, renal trauma, and renal or pararenal tumors. Children born with congenital solitary kidney have a better long-term glomerular filtration rate than those with solitary kidney secondary to nephrectomy later in life. Acute and chronic adaptation processes lead to hyperfiltration followed by fibrosis in the remnant kidney, with further risk of albuminuria, arterial hypertension, and impaired renal function. Protective measures rely on non-pharmacological renoprotection (controlled protein and sodium intake, avoidance/limitation of nephrotoxic agents, keeping normal body mass index, and limitation of tobacco exposure). Lifelong monitoring should include blood pressure and albuminuria assessment, completed by glomerular filtration rate (GFR) estimation in case of abnormal values. In the absence of additional risk factors to solitary kidney, such assessment can be proposed every 5 years. There is no current consensus for indication and timing of pharmacological intervention.

Patient and transplant outcome in infants starting renal replacement therapy before 2 years of age.

Background: Despite major technical improvements in the care of children requiring renal replacement therapy (RRT) before 2 years of age, the management of those patients remains challenging and transplantation is generally delayed until the child weighs 10 kg or is 2 years old. In this national cohort study, we studied patient and graft survival in children starting RRT before 2 years of age to help clinicians and parents when deciding on RRT initiation and transplantation management. Methods: All children starting RRT before 24 months of age between 1992 and 2012 in France were included through the national Renal Epidemiology and Information Network (REIN) registry. The primary endpoints were patient survival on dialysis and 10-year graft survival. Results: A total of 224 patients were included {62% boys, median age 10.5 months [interquartile range (IQR) 5.8-15.6]}. The 10-year survival rate was 84% (IQR 77-89). Suffering from extrarenal comorbidities was the only factor significantly associated with both an increased risk of death on dialysis [hazard ratio 5.9 (95% confidence interval 1.8-19.3)] and a decreased probability of being transplanted. During follow-up, 174 renal transplantations were performed in 171 patients [median age at first transplantation 30.2 (IQR 21.8-40.7) months]. The 10-year graft survival was 74% (IQR 67-81). Factors associated with graft loss in multivariate analysis were the time spent on dialysis before transplantation, donor/recipient height ratio with an increased risk for both small and tall donors and presenting two human leucocyte antigen-antigen D-related mismatches. Conclusions: This study confirms the good outcome of children starting RRT before 2 years of age. The main question remains when and how to transplant those children. Our study provides data on the optimal morphological and immunological matching in order to help clinicians in their decisions.

Eculizumab treatment in severe pediatric STEC-HUS: a multicenter retrospective study.

BACKGROUND: Hemolytic uremic syndrome related to Shiga-toxin-secreting Escherichia coli infection (STEC-HUS) remains a common cause of acute kidney injury in young children. No specific treatment has been validated for this severe disease. Recently, experimental studies highlight the potential role of complement in STEC-HUS pathophysiology. Eculizumab (EC), a monoclonal antibody against terminal complement complex, has been used in severe STEC-HUS patients, mostly during the 2011 German outbreak, with conflicting results. METHODS: On behalf of the French Society of Pediatric Nephrology, we retrospectively studied 33 children from 15 centers treated with EC for severe STEC-HUS. Indication for EC was neurologic involvement in 20 patients, cardiac and neurologic involvement in 8, cardiac involvement in 2, and digestive involvement in 3. Based on medical status at last follow-up, patients were divided into two groups: favorable (n = 15) and unfavorable outcomes (n = 18). RESULTS: Among patients with favorable outcome, 11/14 patients (79%) displayed persistent blockade of complement activity before each EC reinjection. Conversely, in patients with unfavorable outcome, only 9/15 (53%) had persistent blockade (p = n.s.). Among 28 patients presenting neurological symptoms, 19 had favorable neurological outcome including 17 with prompt recovery following first EC injection. Only two adverse effects potentially related to EC treatment were reported. CONCLUSIONS: Taken together, these results may support EC use in severe STEC-HUS patients, especially those presenting severe neurological symptoms. The study, however, is limited by absence of a control group and use of multiple therapeutic interventions in treatment groups. Thus, prospective, controlled trials should be undertaken.

Development of Reliable and Validated Tools to Evaluate Technical Resuscitation Skills in a Pediatric Simulation Setting: Resuscitation and Emergency Simulation Checklist for Assessment in Pediatrics.

OBJECTIVES: To develop a reliable and validated tool to evaluate technical resuscitation skills in a pediatric simulation setting. STUDY DESIGN: Four Resuscitation and Emergency Simulation Checklist for Assessment in Pediatrics (RESCAPE) evaluation tools were created, following international guidelines: intraosseous needle insertion, bag mask ventilation, endotracheal intubation, and cardiac massage. We applied a modified Delphi methodology evaluation to binary rating items. Reliability was assessed comparing the ratings of 2 observers (1 in real time and 1 after a video-recorded review). The tools were assessed for content, construct, and criterion validity, and for sensitivity to change. RESULTS: Inter-rater reliability, evaluated with Cohen kappa coefficients, was perfect or near-perfect (>0.8) for 92.5% of items and each Cronbach alpha coefficient was ≥0.91. Principal component analyses showed that all 4 tools were unidimensional. Significant increases in median scores with increasing levels of medical expertise were demonstrated for RESCAPE-intraosseous needle insertion (P = .0002), RESCAPE-bag mask ventilation (P = .0002), RESCAPE-endotracheal intubation (P = .0001), and RESCAPE-cardiac massage (P = .0037). Significantly increased median scores over time were also demonstrated during a simulation-based educational program. CONCLUSIONS: RESCAPE tools are reliable and validated tools for the evaluation of technical resuscitation skills in pediatric settings during simulation-based educational programs. They might also be used for medical practice performance evaluations.

Infection-related hospitalizations after kidney transplantation in children: incidence, risk factors, and cost.

BACKGROUND: Infection is the leading cause of death and hospitalization in renal transplant recipients. We describe posttransplant infections requiring hospitalization, their risk factors and cost in a national pediatric kidney transplantation cohort. METHODS: Data on renal transplant recipients <20 years were extracted from the French National Medicoadministrative Hospital Discharge database between 2008 and 2013 and matched with the Renal Transplant Database. We used Cox regression to study risk factors of hospitalization and calculated the instantaneous risk of hospitalization per month for all infections and by infection type. RESULTS: Five hundred and ninety-three patients were included, and 660 infection-related hospitalizations were identified in 260 patients. The leading cause of hospitalization was urinary tract infection (UTI), followed by viral infection (16.6 and 15.6 per 100 person-years, respectively). Risk factors were younger age at transplantation, high number of HLA mismatches, and use cyclosporine rather than tacrolimus as first anticalcineurin treatment. Risk factors varied by infection type. Female gender, uropathy, cold ischemia time, and cyclosporine were associated with increased risk of UTI, while only age at transplantation inversely correlated with virus-related hospitalizations. Instantaneous risk of all infections decreased with time, except for cytomegalovirus (CMV) infection that displayed a peak at 6 months posttransplantation after prophylaxis withdrawal. Total cost of infection-related hospitalizations was 1600 kilo-euro (k€) (933 €/person-years). CONCLUSIONS: This study highlights the high burden of infection in transplanted pediatric patients, especially the youngest. This should be considered both for pretransplantation information and designing procedures aiming to decrease hospitalization rate and duration.

Observations of a large Dent disease cohort.

Dent disease classically combines low-molecular-weight proteinuria, hypercalciuria with nephrocalcinosis, and renal failure. Nephrotic range proteinuria, normal calciuria, and hypokalemia have been rarely reported. It is unknown whether the changes in phenotype observed over time are explained by a decrease in glomerular filtration rate (GFR) or whether there is any phenotype-genotype relationship. To answer this we retrospectively analyzed data from 109 male patients with CLCN5 mutations (Dent-1) and 9 patients with mutation of the OCRL gene (Dent-2). In Dent-1 disease, the estimated GFR decreased with age, by 1.0 to 1.6 ml/min per 1.73 m(2)/yr in the absence and presence of nephrocalcinosis, respectively, with no significant difference. Median values of low-molecular-weight proteinuria were in the nephrotic range and remained at the same level even in late renal disease. End-stage renal disease occurred in 12 patients, at a median age of 40 years. Hypercalciuria decreased with glomerular filtration and was absent in 40% of the patients under 30 and 85% of those over the age of 30. Hypophosphatemia did not resolve with age and calcitriol concentrations were in the upper normal range. Kalemia decreased with age, with half of the patients over the age of 18 presenting with hypokalemia. Thus, no phenotype/genotype correlation was observed in this cohort of patients with Dent disease.

Mutation Update of the CLCN5 Gene Responsible for Dent Disease 1.

Dent disease is a rare X-linked tubulopathy characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis and/or nephrolithiasis, progressive renal failure, and variable manifestations of other proximal tubule dysfunctions. It often progresses over a few decades to chronic renal insufficiency, and therefore molecular characterization is important to allow appropriate genetic counseling. Two genetic subtypes have been described to date: Dent disease 1 is caused by mutations of the CLCN5 gene, coding for the chloride/proton exchanger ClC-5; and Dent disease 2 by mutations of the OCRL gene, coding for the inositol polyphosphate 5-phosphatase OCRL-1. Herein, we review previously reported mutations (n = 192) and their associated phenotype in 377 male patients with Dent disease 1 and describe phenotype and novel (n = 42) and recurrent mutations (n = 24) in a large cohort of 117 Dent disease 1 patients belonging to 90 families. The novel missense and in-frame mutations described were mapped onto a three-dimensional homology model of the ClC-5 protein. This analysis suggests that these mutations affect the dimerization process, helix stability, or transport. The phenotype of our cohort patients supports and extends the phenotype that has been reported in smaller studies.

C3 nephritic factor can be associated with membranous glomerulonephritis.

BACKGROUND: C3 nephritic factor (C3NeF) has been described in association with membranoproliferative glomerulonephritis and is involved in 80 % of cases of dense deposit disease. C3NeF is an immunoglobulin G (IgG) autoantibody which binds to the complement component 3 (C3) convertase C3bBb, thereby inhibiting its decay and leading to massive C3 cleavage. Commonly associated with C3NeF are low C3 levels, decreased total haemolytic complement (CH50) and normal C4 levels. C3NeF patients often present with proteinuria, haematuria and high blood pressure. Evolution to end-stage renal disease is common. Treatment consists of steroids and/or immunosuppressants, with variable efficiency. Renal transplantation is marked by histological recurrence, leading to higher rates of allograft loss. CASES: We report C3NeF in association with membranous glomerulonephritis type 3-4 in two unrelated children. We also demonstrate that, under adequate immunosuppressive therapy, proteinuria is significantly lowered, blood pressure is kept within normal range and long-term renal function remains normal. CONCLUSIONS: C3NeF can be associated with membranous glomerulonephritis in children. Clinical presentation is mild, and mid-term outcome is favourable under adequate therapy. However, complement anomalies persist for several years.

Pharmacokinetics of mycophenolate mofetil in children with lupus and clinical findings in favour of therapeutic drug monitoring.

AIMS: The use of mycophenolate mofetil (MMF) in children with systemic lupus erythematosus (SLE) is increasing. However, the clinical benefit of its monitoring has been scarcely studied, and little is known about its pharmacokinetics in this context. The objectives of the present study were: (i) to describe mycophenolic acid (MPA, the active moiety of MMF) pharmacokinetics, (ii) to develop a Bayesian estimator (BE) allowing the determination AUC (area under the curve) from a limited number of blood samples and (iii) to explore the relationships between exposure indices to MPA and the clinical status in children with SLE. METHODS: This was a retrospective study including 36 children with SLE, extracted from the expert system ISBA, for whom full- pharmacokinetic profiles of MPA were collected together with clinical data. A pharmacokinetic model and a BE were developed using an iterative two stage Bayesian approach. ROC curve analyses and logistic regressions were used to investigate the association of exposure and active disease. RESULTS: A pharmacokinetic model and a BE were developed that allowed good AUC estimation performance (bias ± SD = -0.02 ± 0.15). ROC curve analyses showed that AUC/dose <0.06 and AUC <4 mg l(-1) h were associated with a good sensitivity and specificity for active disease (78%/94% and 94%/56%, respectively). When introduced in a logistic regression model, AUC <44 mg l(-1) h and AUC/dose <0.06 were associated with an increased risk of active disease (OR = 21.2, 95% CI 2.3, 196.1, P = 0.007 and OR = 59.5, 95% CI 5.9, 588.2, P = 0.0005 respectively]. CONCLUSIONS: The developed pharmacokinetic BE could be used to test prospectively the interest of MPA monitoring for limiting relapse of the disease or its progression.

Is the renin-angiotensin system actually hypertensive?

The historical view of the renin-angiotensin system (RAS) is that of an endocrine hypertensive system that is controlled by renin and mediated via the action of angiotensin II on its type 1 receptor. Numerous new angiotensins (Ang) and receptors have been described, the majority being hypotensive and natriuretic, namely Ang-(1-7) and its receptor rMas. Renin and its precursor (pro-renin) can bind their common receptor. In addition to the production of Ang II, this receptor triggers intracellular effects. Given the control of renin production by intracellular calcium, calcium homeostasis is of particular importance. Ang-(1-12), which is not controlled by renin, is converted to several different angiotensin peptides and is a new pathway of the RAS. Local RAS enzymes produce or transform the different hyper- or hypotensive angiotensin within vessels and organs, but also in blood through circulating forms of the enzymes. In the kidney, a powerful local vascular RAS allows for the independence of renal vascularization from systemic control. Moreover, the kidney also contains an independent urinary RAS, which counterbalances the systemic RAS and coordinates proximal and distal sodium reabsorption. The systemic and local effects of renal RAS cannot be analyzed without taking into account the antagonistic effect of renalase. Our concept of RAS needs to evolve to take into account its dual potentiality (hyper- or hypotensive).

Long-term remission of atypical HUS with anti-factor H antibodies after cyclophosphamide pulses.

BACKGROUND: Anti-complement factor H (CFH) autoantibody (Ab)-associated atypical hemolytic uremic syndrome (aHUS) has a poor prognosis, but no consensus exists on its treatment. METHODS: We report the follow-up of four children with anti-CFH Ab (8,000 to >32,000 arbitrary units)-associated aHUS after plasma exchanges (PEs), prednisone, and cyclophosphamide pulse therapy with the evolution of anti-CFH Ab titers and kidney function. RESULTS: Patient 1 received PEs + prednisone + cyclophosphamide pulses after two relapses following PEs and then PEs + rituximab. The other three patients were treated with PEs + prednisone + cyclophosphamide pulses as a first-line therapy. In our four patients, the induction protocol combining PEs + prednisone + cyclophosphamide pulses led to a rapid and sustained remission up to 6 years, 4 years and 4 months without any maintenance therapy. Kidney function was normal and anti-CFH Ab titer decreased, but remained detectable during remission without any clinical or biological signs of relapse. CONCLUSIONS: We demonstrate the long-term efficiency and safety of cyclophosphamide pulses combined with PEs and prednisone in anti-CFH Ab-associated aHUS leading to a prolonged decrease in anti-CFH Ab titers and prevention of relapses without the need for maintenance therapy.

Cystinosin is a melanosomal protein that regulates melanin synthesis.

Cystinosis is a rare autosomal recessive disease characterized by cystine crystal accumulation leading to multiorgan dysfunctions and caused by mutation in CTNS. CTNS encodes cystinosin, a cystine/H(+) symporter that exports cystine out of the lysosomes. Patients with cystinosis frequently exhibit blond hair and fair complexion, suggesting an alteration in melanogenesis. However, the pigmentation singularities of these patients have not been studied, and the role of cystinosin in melanogenesis has remained unknown. In our study, a clinical evaluation of 27 patients with cystinosis showed that 44% had a cutaneous pigmentation dilution compared to their relatives. Analysis of the hair melanin content in these patients by HPLC demonstrated a 50% decrease in eumelanin (4360 vs. 9360 ng/mg), and a 2-fold increase in pheomelanin (53 vs. 20 ng/mg), the yellow/red pigments. Cystinosin-deficient mice also showed a 4-fold increase in hair pheomelanin content. In vitro studies showed that cystinosin was located at melanosomes. CTNS silencing led to a 75% reduction of melanin synthesis that was caused by a degradation of tyrosinase by lysosomal proteases. Our results objectify the pigmentation defect in patients with cystinosis. We also identify the role of CTNS in melanogenesis and add a new gene to the list of the genes involved in the control of skin and hair pigmentation.

In vivo reflectance confocal microscopy of the skin: a noninvasive means of assessing body cystine accumulation in infantile cystinosis.

BACKGROUND: Patients with infantile nephropathic cystinosis have progressive accumulation of cystine in tissues leading to delayed extrarenal complications. No simple tool is available to evaluate the level of body cystine accumulation. OBJECTIVE: We sought to determine the value of in vivo reflectance confocal microscopy of the skin in patients with infantile nephrogenic cystinosis. METHODS: Nine patients and control subjects were recruited for this study. Images were acquired by means of a near-infrared reflectance confocal laser scanning microscope. RESULTS: Scattered bright particles within the papillary dermis were observed in all patients but not in control subjects. The density of particles ranged from numerous (+++) to very few (+/-) and their distribution was heterogeneous. Electron microscopy confirmed that these particles corresponded to cystine crystal deposits within dermal fibroblasts. The density of cystine crystals within the dermis was greater in older patients, in patients with a high leukocyte cystine concentration, and with delayed cysteamine therapy. There was no correlation between the density of cystine deposits and renal disease or hypopigmentation but high levels of deposition occurred in association with extrarenal manifestations. LIMITATIONS: This is a preliminary study on a small sample of patients. Repeated examination and longer follow-up is necessary. CONCLUSION: In vivo reflectance confocal microscopy of the skin appears to be a noninvasive means of assessing body cystine accumulation in infantile cystinosis and could be used as a complementary marker of treatment response in addition to leukocyte cystine measurement.

REIN: a tool at the service of the paediatric patients / REIN : un outil au service des patients pédiatriques

On the occasion of the 20th anniversary of the REIN (French Renal Epidemiology and Information Network), a summary work on the contributions of the national French ESKD register was carried out. On the issue of paediatric CKD patients, the following key messages were retained. Paediatric stage 5 chronic kidney disease (CKD) has particularities that require to be analysed and taken into account because the mortality of these patients remains 30 times higher than that of children of the same age. The REIN registry enables illustrating the specificities of stage 5 CKD in the paediatric age-group in France and providing a set of indicators making it possible to describe the future of these patients as well as the choices made concerning the modalities of replacement therapy. As compared to other European countries, the incidence and prevalence of stage 5 CKD in France is in the middle range for children under 15 and 20 years old. Renal transplant is by far the leading treatment for stage 5 CKD in children and adolescents under 18 years of age in France, allowing to offer these patients the best possible life expectancy. Owing to the small volume of patients, only a nationwide registry can provide an unbiased view and enables analysing this population requiring a hyperspecialised treatment. The participation of French paediatric nephrologists in the REIN French registry also enables providing input to the European registry (ESPN/ERA www.espn-reg.org/index.jsp) and the international registry (IPNA https://ipna-registry.org) (Consulted on September 15th 2022) and thus the possibility of international studies, which are vital to be in line with an approach to improving practices.

À l'occasion des 20 ans du REIN (Réseau Epidémiologie et Information en Néphrologie), un travail de synthèse sur les apports du registre a été mené. Sur la question des patients pédiatriques, les messages clés suivants ont été retenus. La maladie rénale chronique (MRC) stade 5 pédiatrique a des particularités qui nécessitent d'être analysées et prises en compte car la mortalité de ces patients reste 30 fois supérieure à celle des enfants du même âge. Le registre REIN permet d'illustrer les spécificités de la MRC stade 5 à l'âge pédiatrique en France et de fournir un ensemble d'indicateurs permettant de décrire le devenir de ces patients ainsi que les choix faits concernant les modalités de traitement de suppléance. En comparaison à d'autres pays européens, l'incidence et la prévalence de la MRC stade 5 en France se situent dans les valeurs moyennes chez les enfants de moins de 15 et 20 ans. La transplantation rénale est de loin le premier traitement de la MRC stade 5 parmi les enfants et les adolescents de moins de 18 ans en France, permettant d'offrir à ces patients la meilleure espérance de vie possible. En raison du petit volume de patients, seul un registre à l'échelon national permet d'avoir une vision non biaisée et d'analyser cette population nécessitant une prise en charge hyperspécialisée. La participation des néphropédiatres français au registre français REIN permet aussi d'alimenter le registre européen (ESPN/ ERA www.espn-reg.org/index.jsp) et le registre international (IPNA https://ipna-registry.org) (Consulté le 15 septembre 2022) et ainsi la possibilité d'études internationales, indispensables pour s'inscrire dans une démarche d'amélioration des pratiques.