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Background: Kidney transplantation (KTx) from small donors is associated with inferior graft survival in registry studies, whereas single-center studies show favorable results., Methods: We compared 175 pediatric KTx from small donors ≤20 kg (SDKTx) with 170 age-matched recipients from adult donors (ADKTx) from 20 centers within the Cooperative European Paediatric Renal Transplant Initiative registry. Graft survival and estimated glomerular filtration rate (eGFR) were analyzed by Cox regression and mixed models. Detailed data on surgical and medical management were tested for association with graft survival., Results: One-year graft survival was lower after SDKTx compared with ADKTx (90.9% versus 96.5%; odds ratio of graft loss, 2.92; 95% confidence interval [CI], 1.10-7.80; P  = 0.032), but 5-y graft survival was comparable (90.9% versus 92.7%; adjusted hazard ratio of graft loss 1.9; 95% CI, 0.85-4.25; P  = 0.119). SDKTx recipients had an annual eGFR increase of 8.7 ± 6.2 mL/min/1.73 m² compared with a decrease of 6.9 ± 5.7 mL/min/1.73 m² in ADKTx recipients resulting in a superior 5-y eGFR (80.5 ± 25.5 in SDKTx versus 65.7 ± 23.1 mL/min/1.73 m² in ADKTx; P  = 0.008). At 3 y posttransplant, eGFR after single SDKTx was lower than after en bloc SDKTx (86.6 ± 20.4 versus 104.6 ± 35.9; P  = 0.043) but superior to ADKTx (68.1 ± 23.9 mL/min/1.73 m²). Single-kidney SDKTx recipients had a lower rate of hypertension at 3 y than ADKTx recipients (40.0% versus 64.7%; P  = 0.008)., Conclusions: Compared with ADKTx, 5-y graft function is superior in SDKTx and graft survival is similar, even when performed as single KTx. Utilizing small donor organs, preferably as single kidneys in experienced centers, is a viable option to increase the donor pool for pediatric recipients., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: The unphysiological composition of peritoneal dialysis (PD) fluids induces progressive peritoneal fibrosis, hypervascularization and vasculopathy. Information on these alterations after kidney transplantation (KTx) is scant., Methods: Parietal peritoneal tissues were obtained from 81 pediatric patients with chronic kidney disease stage 5 (CKD5), 72 children on PD with low glucose degradation product (GDP) PD fluids, and from 20 children 4-8 weeks after KTx and preceding low-GDP PD. Tissues were analyzed by digital histomorphometry and quantitative immunohistochemistry., Results: While chronic PD was associated with peritoneal hypervascularization, after KTx vascularization was comparable to CKD5 level. Submesothelial CD45 counts were 40% lower compared with PD, and in multivariable analyses independently associated with microvessel density. In contrast, peritoneal mesothelial denudation, submesothelial thickness and fibrin abundance, number of activated, submesothelial fibroblasts and of mesothelial-mesenchymal transitioned cells were similar after KTx. Diffuse peritoneal podoplanin positivity was present in 40% of the transplanted patients. In subgroups matched for age, PD vintage, dialytic glucose exposure and peritonitis incidence, submesothelial hypoxia-inducible factor 1-alpha abundance and angiopoietin 1/2 ratio were lower after KTx, reflecting vessel maturation, while arteriolar and microvessel p16 and cleaved Casp3 were higher. Submesothelial mast cell count and interleukin-6 were lower, whereas transforming growth factor-beta induced pSMAD2/3 was similar as compared with children on PD., Conclusions: Peritoneal membrane damage induced with chronic administration of low-GDP PD fluids was less severe after KTx. While peritoneal microvessel density, primarily defining PD transport and ultrafiltration capacity, was normal after KTx and peritoneal inflammation less pronounced, diffuse podoplanin positivity and profibrotic activity were prevalent., (© The Author(s) 2023. Published by Oxford University Press on behalf of the ERA.)

Background: Improved management of growth impairment might have resulted in less growth retardation after pediatric kidney transplantation (KT) over time. We aimed to analyze recent longitudinal growth data after KT in comparison to previous eras, its determinants, and the association with transplant outcome in a large cohort of transplanted children using data from the European Society for Paediatric Nephrology/European Renal Association and European Dialysis and Transplant Association Registry., Methods: A total of 3492 patients transplanted before 18 years from 1990 to 2012 were included. Height SD scores (SDS) were calculated using recent national or European growth charts. We used generalized equation models to estimate the prevalence of growth deficit and linear mixed models to calculate adjusted mean height SDS., Results: Mean adjusted height post-KT was -1.77 SDS. Height SDS was within normal range in 55%, whereas 28% showed moderate, and 17% severe growth deficit. Girls were significantly shorter than boys, but catch-up growth by 5 years post-KT was observed in both boys and girls. Children <6 years were shortest at KT and showed the greatest increase in height, whereas there was no catch-up growth in children transplanted >12., Conclusions: Catch-up growth post-KT remains limited, height SDS did not improve over time, resulting in short stature in nearly half of transplanted children in Europe.

Background: Children with congenital nephrotic syndrome (CNS) commonly develop end stage renal failure in infancy and require dialysis, but little is known about the complications and outcomes of dialysis in these children., Methods: We conducted a retrospective case note review across members of the European Society for Pediatric Nephrology Dialysis Working Group to evaluate dialysis management, complications of dialysis, and outcomes in children with CNS., Results: Eighty children (50% male) with CNS were identified form 17 centers over a 6-year period. Chronic dialysis was started in 44 (55%) children at a median age of 8 (interquartile range 4-14) months. Of these, 17 (39%) were on dialysis by the age of 6 months, 30 (68%) by 1 year, and 40 (91%) by 2 years. Peritoneal dialysis (PD) was the modality of choice in 93%, but 34% switched to hemodialysis (HD), largely due to catheter malfunction (n = 5) or peritonitis (n = 4). The peritonitis rate was 0.77 per patient-year. Weight and height SDS remained static after 6 months on dialysis. In the overall cohort, at final follow-up, 29 children were transplanted, 18 were still on dialysis (15 PD, 3 HD), 19 were in pre-dialysis chronic kidney disease (CKD), and there were 14 deaths (8 on dialysis). Median time on chronic dialysis until transplantation was 9 (6-18) months, and the median age at transplantation was 22 (14-28) months., Conclusions: Infants with CNS on dialysis have a comparable mortality, peritonitis rate, growth, and time to transplantation as infants with other primary renal diseases reported in international registry data.

Objective: Vascular thrombosis (VT) in pediatric kidney transplantation (KT) is a dreaded event that leads to graft loss in almost 100% of cases. In recent years, VT has become the most common cause of early graft loss. The aim of this study was to analyze our experience in diagnosis and treatment of VT and the impact of a new management protocol on patient outcome., Methods: We conducted a retrospective study of 176 consecutive KT performed at our institution by the pediatric urology team between January 2000 and December 2015 and identified patients with VT. A protocol of prevention and early detection of VT was introduced in 2012., Results: Out of 176 KT, nine cases of VT were identified (5.1%). The mean recipient age was 5.1 years (SD 4.9 years) and mean weight was 22.28 kg (SD 15.6 kg). Diagnosis was intraoperative in two cases and within the first 24 h after surgery in the remaining seven. Immediate surgical exploration was performed after diagnosis in all. Of the five episodes that occurred before 2012, all developed complete graft ischemia requiring transplantectomy. However, in the four cases diagnosed after 2012, graft perfusion could be restored in three, and abdominal wall closure with a mesh and delayed sequentially closure under ultrasound guidance was performed. With a follow-up of 30, 25, and 20 months, the three recovered grafts are still functioning normally., Conclusions: Increased awareness and the application of a protocol for prevention, detection and treatment of VT in pediatric KT can prevent graft loss. Immediate surgical intervention is mandatory after diagnosis. Avoiding compartment syndrome with delayed sequential closure may be useful to improve graft survival., (Copyright © 2018 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Introduction: Liver-kidney transplantation is a rare procedure in children, with just ten to 30 cases performed annually worldwide. The main indications are autosomal recessive polycystic liver-kidney disease and primary hyperoxaluria. This study aimed to report outcomes of liver-kidney transplantation in a cohort of pediatric patients., Methods: We retrospectively analyzed all pediatric liver-kidney transplantations performed in our center between September 2000 and August 2015. Patient data were obtained by reviewing inpatient and outpatient medical records and our transplant database., Results: A total of 14 liver-kidney transplants were performed during the study period, with a median patient age and weight at transplant of 144.4 months (131.0-147.7) and 27.3 kg (12.0-45.1), respectively. The indications for liver-kidney transplants were autosomal recessive polycystic liver-kidney disease (8/14), primary hyperoxaluria -1 (5/14), and idiopathic portal hypertension with end-stage renal disease (1/14). Median time on waiting list was 8.5 months (5.7-17.3). All but two liver-kidney transplants were performed simultaneously. Patients with primary hyperoxaluria-1 tended to present a delayed recovery of renal function compared with patients transplanted for other indications (62.5 vs 6.5 days, respectively, P 0.076). Patients with liver-kidney transplants tended to present a lower risk of acute kidney rejection than patients transplanted with an isolated kidney transplant (7.2% vs 32.7%, respectively; P < 0.07). Patient and graft survival at 1, 3, and 5 years were 100%, 91.7%, 91.7%, and 91.7%, 83.3%, 83.3%, respectively. No other grafts were lost., Conclusion: Long-term results of liver-kidney transplants in children are encouraging, being comparable with those obtained in isolated liver transplantation.

Objective: Pediatric kidney transplantation (KT) in small children is assumed to be related to potential surgical complications that may cause severe morbidity and graft loss. The aim of our study was to analyze the outcome of KT recipients weighing ≤15 kg, focusing on surgical complications, associated morbidity and mortality, as well as allograft loss., Methods: We reviewed our retrospective institutional database for recipients of KT between January 2000 and December 2014 with body weight ≤15 kg., Results: Forty-four children weighing ≤15 kg, out of a total of 164 children (26.8%), received a deceased donor KT at our center during the study period. Mean weight was 10.10 ± 2.9 kg (3-15 kg), and weight was ≤10 kg in 23 patients (52.3%). The allograft was implanted intraperitoneally in two cases (4.5%) and extraperitoneally in the remaining 42 (95.5%). Two patients received a simultaneous double liver-kidney transplant. Postoperative complications appeared in 10 patients (22.7%) and eight required reintervention. Five allografts (11.4%) were lost secondary to surgical complications. No statistically significant differences in surgical complications were observed when compared with patients weighing >15 kg. Actuarial graft survival was 81% and 73% at 1 and 5 years, respectively. No significant differences in graft survival were observed compared with patients >15 kg. Mean follow-up was 84.95 ± 50 months (1-190 months)., Conclusions: Our results demonstrate that KT in children weighing ≤15 kg is challenging but not associated with increased risk of surgical complications or early graft loss., (Copyright © 2017 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.)

Objective: To review our single-center experience in managing posttransplant lymphoceles in pediatric kidney recipients. Lymphoceles are well-known complications after pediatric kidney transplantation (KT). However, there is no standard treatment for lymphoceles, and the literature lacks consensus on which is the most appropriate approach., Materials and Methods: We reviewed our retrospective institutional database for recipients of pediatric KT performed between January 2000 and December 2015 who developed lymphoceles., Results: Out of the 176 patients who underwent KT, lymphoceles occurred in 9 (5.1%) patients. The mean age of recipients in this group was 12.8 years (standard deviation [SD] 4.8) (r: 1-17) and the mean body weight was 43.1 kg (SD 18.8) (r: 9.5-69). Mean lymphocele onset was 32.2 days (SD 23.4) (r: 11-85) post transplantation. Six patients presented with increased serum creatinine from the baseline, whereas 3 patients remained asymptomatic. Ultrasound was the primary diagnostic procedure in all patients. Lymphoceles resolved spontaneously in asymptomatic patients (n = 3), and thus these patients were not further treated. All symptomatic patients (n = 6) were treated: 2 underwent percutaneous catheter drainage and 4 underwent transcatheter sclerotherapy (TS). The main sclerosing agent used was povidone-iodine. In 3 patients, TS with povidone-iodine failed, and they underwent additional procedures: 2 underwent TS with polidocanol and 1 underwent open drainage. There was no graft loss in any of the patients, and no recurrence was documented during a follow-up period of mean 30.3 months (SD 15.6) (r: 7-57)., Conclusion: There is no gold-standard treatment for lymphoceles in children, and reports in the literature on the topic are scarce. Percutaneous catheter drainage with or without TS is safe and effective, although it can lengthen hospitalization and increase morbidity., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Experimental findings indicate that sirolimus (SRL) inhibits longitudinal growth by mechanisms potentially related to its inhibitory effects on both cell proliferation and expression of vascular endothelial growth factor (VEGF). The aim of this study was to investigate the growth pattern of kidney-transplanted children treated with SRL in a multicenter observational clinical study. Height, change in height SD (Δ height) and growth velocity of pediatric patients with renal transplant were calculated at 0, 6, 12, and 24 months after starting SRL. Controls of kidney-transplanted children not treated with SRL were matched by age, gender, renal function, and dose of corticosteroids. Sixty-eight children (34 SRL, 34 controls) were enrolled in the study. Nephrotoxicity was the most frequent indication to start therapy with SRL. SRL exerted an adverse effect on growth as demonstrated by significantly lower (p < 0.05) growth velocity (cm/year) and smaller change in height SD in the SRL group after 6 (4.08 vs. 6.56 and -0.05 vs. 0.14), 12 (4.44 vs. 6.11 and -0.03 vs. 0.28) and 24 (4.53 vs. 6.03 and -0.04 vs. 0.53) months of treatment. This study suggests that SRL therapy may interfere with growth of kidney-transplanted children. This undesirable effect needs to be taken into account when considering a switch to SRL and confirmed in further prospective trials including larger number of patients.

Background: Hyperhomocysteinaemia represents an important cause of morbidity in recipients of renal transplants, but few investigations have been carried out to evaluate the status of the methylation cycle and its relation with levels of new cardiovascular biomarkers, such as asymmetric dimethylarginine (ADMA)., Methods: Twenty-six children and adolescents aged 7-18 years (17 male, 9 female) with stable renal transplants were recruited for the study. None had received treatment with folate, vitamin B(12) or statins. Levels of ADMA in plasma and of components of the methylation cycle and arginine (Arg)-creatine pathway in plasma and urine were analysed by specific analytical methods. Results were compared to those obtained by us with identical methods in healthy children of similar age., Results: Concentrations of homocysteine (Hcys), S-adenosylhomocysteine (SAH) and ADMA were significantly higher, while S-adenosylmethionine (SAM)/SAH and Arg/ADMA ratios were significantly lower than controls. Arg/ADMA ratio correlated with plasma guanidinoacetate. The components of the methylation cycle, Hcys and SAH correlated with renal function., Conclusions: Children with renal transplant showed low methylation power (SAM/SAH) mainly due to increased levels of SAH which acts as a cardiovascular biomarker. Elevated values of ADMA and low Arg/ADMA coefficients also represent a novel finding because it inhibits nitric oxide synthesis contributing to endothelial dysfunction and cardiovascular risk in such patients.

The health-related quality of life (HRQOL) of adolescents with end-stage renal disease (ESRD) is an important marker of disease burden. Our aims were to investigate HRQOL in a group of children and adolescents with ESRD and to compare them with the reference population norms. Ours was a cross-sectional study of 81 patients aged 10 years to 21 years with ESRD (68 with kidney transplants and 13 on dialysis) at five Spanish paediatric nephrology centres. HRQOL was investigated with the Spanish version of the child health and illness profile, adolescent edition (CHIP-AE). Clinical variables such as underlying diagnosis, number of rejection episodes, pre-emptive transplantation, anaemia and height were also analysed. No differences were found between patients with kidney transplants and their healthy peers in any domain or sub-domain of CHIP-AE. The group on dialysis scored lower than healthy controls and patients with transplants for satisfaction with health. Discomfort was higher in patients with transplants who had suffered one rejection episode. Physical discomfort was increased in anaemic patients with transplants. Short patients scored less in the satisfaction domain, with lower self-esteem and lower satisfaction with health. Adolescents with kidney transplants had better satisfaction with health than the group on dialysis, which matched the level of a healthy population. Further long-term prospective research is warranted.

Cardiovascular disease is an important cause of morbidity in recipients of renal transplants. The aim of the present study was to analyze the status of the arginine-creatine pathway in such patients, given the relationship between the arginine metabolism and both renal function and the methionine-homocysteine cycle. Twenty-nine children and adolescents (median age 13, range 6-18 years), who had received a renal allograft 14.5-82.0 months before, were recruited for the study. On immunosuppressive therapy, all patients evidenced an adequate level of renal function. Plasma concentrations of homocysteine and glycine were significantly higher, whereas urinary excretions of guanidinoacetate and creatine were significantly lower than controls. Urinary excretions of guanidinoacetate and creatine correlated positively with creatinine clearance. Urinary excretion of creatine was negatively correlated with plasma concentration of homocysteine. The demonstration of disturbances in the arginine-creatine pathway in patients with well-functioning renal transplants and in absence of chronic renal failure represents a novel finding. We speculate that the low urinary excretion of guanidinoacetate and creatine is probably related to the nephrotoxic effect of immunosuppressive therapy and to defective methylation associated with the presence of hyperhomocysteinemia.

Historically, specific mutations in WT1 gene have been associated with distinct syndromes based on phenotypic characteristics, including Denys-Drash syndrome (DDS), Frasier syndrome (FS), Meacham syndrome, and WAGR syndrome. DDS is classically defined by the triad of steroid-resistant nephrotic syndrome (SRNS) onset in the first year of life, disorders of sex development (DSD), and a predisposition to Wilms tumor (WT). Currently, a paradigm shift acknowledges a diverse spectrum of presentations beyond traditional syndromic definitions. Consequently, the concept of WT1-related disorders becomes more precise. A genotype–phenotype correlation has been established, emphasizing that the location and type of WT1 mutations significantly influence the clinical presentation, the condition severity, and the chronology of patient manifestations. Individuals presenting with persistent proteinuria, with or without nephrotic syndrome, and varying degrees of kidney dysfunction accompanied by genital malformations should prompt suspicion of WT1 mutations. Recent genetic advances enable a more accurate estimation of malignancy risk in these patients, facilitating a conservative nephron-sparing surgery (NSS) approach in select cases, with a focus on preserving residual kidney function and delaying nephrectomies. Other key management strategies include kidney transplantation and addressing DSD and gonadoblastoma. In summary, recent genetic insights underscore the imperative to implement individualized, integrated, and multidisciplinary management strategies for WT1-related disorders. This approach is pivotal in optimizing patient outcomes and addressing the complexities associated with these diverse clinical manifestations. [ABSTRACT FROM AUTHOR]

Background: Vesico‐ureteral reflux (VUR) is considered to be a risk factor for recurrent febrile urinary tract infections and impaired renal transplant survival. Methods: An online survey supported by the European Society for Paediatric Nephrology was designed to evaluate current management strategies of VUR in native and transplanted kidneys of recipients aged <18 years. Results: Seventy‐three pediatric transplant centers from 32 countries contributed to the survey. All centers performed urological evaluation prior to pediatric kidney transplantation (KTx) with subsequent interdisciplinary discussion. Screening for VUR in native kidneys (30% in all, 70% in selected patients) led to surgical intervention in 78% (11% in all, 89% in selected patients) with a decided preference of endoscopic intervention over ureterocystoneostomy. Following KTx, continuous antibiotic prophylaxis was applied in 65% of the patients and screening for allograft VUR performed in 93% of selected patients. The main management strategies of symptomatic allograft VUR were continuous antibiotic prophylaxis (83%) and surgical treatment (74%) (endoscopic intervention 55%, redo ureterocystoneostomy 26%). Conclusions: This survey demonstrates the high variability in the management of VUR in pediatric KTx recipients, points to knowledge gaps, and might serve as a starting point for improving the care for patients with VUR in native and transplanted kidneys. [ABSTRACT FROM AUTHOR]

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC; OMIM 248250) is a rare autosomal recessive kidney disease caused by mutations in the CLDN16 or CLDN19 genes encoding the proteins claudin-16 and claudin-19, respectively. These are involved in paracellular magnesium and calcium transport in the thick ascending limb of Henle's loop and account for most of the magnesium reabsorption in the tubules. FHHNC is characterized by hypomagnesaemia, hypercalciuria, and nephrocalcinosis, and progresses to kidney failure, requiring dialysis and kidney transplantation mainly during the second to third decades of life. Patients carrying CLDN19 mutations frequently exhibit associated congenital ocular defects leading to variable visual impairment. Despite this severe clinical course, phenotype variability even among siblings has been described in this disease, suggesting unidentified epigenetic mechanisms or other genetic or environmental modifiers. Currently, there is no specific therapy for FHHNC. Supportive treatment with high fluid intake and dietary restrictions, as well as magnesium salts, thiazides, and citrate, are commonly used in an attempt to retard the progression of kidney failure. A kidney transplant remains the only curative option for kidney failure in these patients. In this review, we summarize the current knowledge about FHHNC and discuss the remaining open questions about this disorder. [ABSTRACT FROM AUTHOR]

Primary or idiopathic focal segmental glomerulosclerosis (FSGS) is a kidney entity that involves the podocytes, leading to heavy proteinuria and in many cases progresses to end-stage renal disease. Idiopathic FSGS has a bad prognosis, as it involves young individuals who, in a considerably high proportion (∼15%), are resistant to corticosteroids and other immunosuppressive treatments as well. Moreover, the disease recurs in 30–50% of patients after kidney transplantation, leading to graft function impairment. It is suspected that this relapsing disease is caused by a circulating factor(s) that would permeabilize the glomerular filtration barrier. However, the exact pathologic mechanism is an unsettled issue. Besides its poor outcome, a major concern of primary FSGS is the complexity to confirm the diagnosis, as it can be confused with other variants or secondary forms of FSGS and also with other glomerular diseases, such as minimal change disease. New efforts to optimize the diagnostic approach are arising to improve knowledge in well-defined primary FSGS cohorts of patients. Follow-up of properly classified primary FSGS patients will allow risk stratification for predicting the response to different treatments. In this review we will focus on the diagnostic algorithm used in idiopathic FSGS both in native kidneys and in disease recurrence after kidney transplantation. We will emphasize those potential confusing factors as well as their detection and prevention. In addition, we will also provide an overview of ongoing studies that recruit large cohorts of glomerulopathy patients (Nephrotic Syndrome Study Network and Cure Glomerulonephropathy, among others) and the experimental studies performed to find novel reliable biomarkers to detect primary FSGS. [ABSTRACT FROM AUTHOR]

Background: COVID-19 was declared a global health emergency. Since children are less than 1% of reported cases, there is limited information to develop evidence-based practice recommendations. The objective of this study was to rapidly gather expert knowledge and experience to guide the care of children with chronic kidney disease during the COVID-19 pandemic. Methods: A four-round multi-center Delphi exercise was conducted among 13 centers in 11 European countries of the European Pediatric Dialysis Working Group (EPDWG) between March, 16th and 20th 2020. Results were analyzed using a mixed methods qualitative approach and descriptive statistics. Results: Thirteen COVID-19 specific topics of particular need for guidance were identified. Main themes encompassed testing strategies and results (n = 4), changes in use of current therapeutics (n = 3), preventive measurements of transmission and management of COVID-19 (n = 3), and changes in standard clinical care (n = 3). Patterns of center-specific responses varied according to regulations and to availability of guidelines. Conclusions: As limited quantitative evidence is available in real time during the rapid spread of the COVID-19 pandemic, qualitative expert knowledge and experience represent the best evidence available. This Delphi exercise demonstrates that use of mixed methodologies embedded in an established network of experts allowed prompt analysis of pediatric nephrologists' response to COVID-19 during this fast-emerging public health crisis. Such rapid sharing of knowledge and local practices is essential to timely and optimal guidance for medical management of specific patient groups in multi-country health care systems such as those of Europe and the US. [ABSTRACT FROM AUTHOR]

Background Denys–Drash syndrome (DDS) is a rare disease caused by mutations in exons 8 and 9 of the WT1 gene. It is characterized by the association of early onset steroid-resistant nephrotic syndrome (SRNS), Wilms' tumour and, in some patients, intersex disorders, with increasing risk of gonadoblastoma. There are few published data concerning the long-term outcome of patients with DDS. The aim of this study was to report our experience. Methods Data were collected from five children (three boys) with confirmed DDS diagnosed from 1996 to 2017. The mean follow-up of these patients was 16 years. Results The patients presented with SRNS and diffuse mesangial sclerosis at renal biopsy. All patients were hypertensive and progressed to end-stage kidney disease, initiating dialysis at a mean age of 28 months. Three patients developed Wilms' tumour 9 months after the SRNS was identified, which was treated by nephrectomy and chemotherapy. All five patients received kidney transplantation. SRNS did not recur after transplantation in any of the patients and graft survival was similar to that of other kidney transplant recipients in our programme. All three boys had ambiguous genitalia and cryptorchidism but a confirmed male karyotype (46, XY). One girl presented with gonadal agenesis, whereas the other one had normal female ovarian tissue and external genitalia. Both girls had a female karyotype (46, XX). Gonadoblastoma was not observed at any case. Conclusions Early DDS recognition in patients with SRNS is crucial due to its low prevalence, the specific treatment approach required and early detection of Wilms' tumour. Few data are available regarding long-term outcomes. [ABSTRACT FROM AUTHOR]

Despite survival rates after pediatric kidney transplantation (KT) are on the rise it is still likely that most pediatric recipients will require more than one retransplant in their lifetime. The earlier the age at the first KT the higher is the risk of repeat pediatric kidney transplantation (RPKT). The current study aims to analyze the outcomes of repeat pediatric kidney transplantation (RPKT) among pediatric kidney transplant recipients focusing on surgical complications and compare the outcomes of second and subsequent grafts with those of the first kidney graft. Retrospective study of RPKT (<18 years) undertaken between January 2000–2020. We analyzed primary etiology of renal disease, time to graft loss (GL), etiology of initial graft failure, history of acute rejection, previous delayed graft function, HLA-mismatches at the initial transplant, surgical complications and outcomes. Additionally, we compared the characteristics and outcomes of patients who underwent RPKT (group 1) with those who received a first kidney graft (group 2). Out of 229 kT, 59 patients underwent RPKT (26 females/33 males). At the time of RPKT median age was 11.37 years (SD:5.7). The most frequent primary renal disease was congenital nephrotic syndrome in 11 (18.6%). Fifty-four (91.5%) were on renal replacement therapy at the time of transplant. Forty-one patients received their second KT (69.5%), 14 (23.7%) the third, 3 (5.1%) the fourth and 1 (1.7%) the fifth. Transplant graft nephrectomy (GN) was performed in 26 patients (44.1%) prior to retransplantation. Fifty-four (91.5%) received a cadaveric graft and 5 (8.5%) a living-related graft. An extraperitoneal approach was achieved in 53 patients (89.8%), whereas in the remaining 6 (10.2%) the graft was placed intraperitoneally. We observed 10 surgical complications (16.9%): 9 major which required reintervention and 1 minor (perirenal hematoma). No vascular complications were observed and none of the surgical complications were involved in graft loss. Graft survival at 1,3 and 5 years was 91%, 84% and 73% respectively. The most frequent cause of GL was chronic graft nephropathy in 15 (25.4%). After a mean follow-up of 9.40 years (SD: 4.7) only 2 patients died (3.4%), both with functioning grafts. Pediatric recipients of second and subsequent kidney grafts constitute a remarkable high-risk population but are becoming more frequent at reference pediatric transplant centers. RPKT is technically challenging but can yield good results. In our series overall the incidence of surgical complications and particularly vascular complications was low. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Many factors may impact upon choice of renal replacement therapy (RRT) for children and adolescents, including patient and family choice, patient size and distance from the renal centre as well as logistic issues such as facilities and staffing at the unit. We report a survey of factors influencing treatment choice in 14 European paediatric nephrology units. Methods: A questionnaire was developed by consensus and completed by 14 members of the European Paediatric Dialysis Working Group on facilities, staffing and family assessments impacting on choice of therapy as well as choice of therapy for 97 patients commencing initial RRT in 2011. Results: All units offered all modalities of RRT, but there were limitations for pre-emptive transplantation (PET) and largely adult surgical dependence for creation of arteriovenous fistulae and transplantation. The average waiting time for a deceased donor kidney was 18.5 (range 3-36) months. Full time dietetic support was available in six of the 14 units. There was no social worker, psychology, play therapy or teaching support in three, two, seven and four units, respectively. Assessment by other members of the multidisciplinary team and home visits before choice of therapy was carried out in 50 % of units, and although all patients were discussed at team meetings, the medical opinion predominated. In terms of types of RRT, 50 % of patients were commenced on chronic peritoneal dialysis (PD), 34 % on haemodialysis (HD) and 16 % underwent pre-emptive transplantation (PET). Chronic PD predominated in patients aged <5 years and HD predominated in those aged >10 years. Patient and family choice and age or size of patient were predominant factors in choice of therapy with a predictable decline in renal function favouring PET and social factors HD. Conclusions: Chronic peritoneal dialysis predominated as primary choice of RRT, especially in younger children. The PET rates remain low. The influence of surgeons predominanted, and national transplant rules may be significant. Most units had insufficient multiprofessional support, which may impact upon initial choice of therapy as well as sustaining families through RRT. [ABSTRACT FROM AUTHOR]

Background In recent years, increased efforts have been undertaken to address the needs of patients with rare diseases by international initiatives and consortia devoted to rare disease research and management. However, information on the overall prevalence of rare diseases within the end-stage renal disease (ESRD) population is limited. The aims of this study were (i) to identify those rare diseases within the ERA–EDTA Registry for which renal replacement therapy (RRT) is being provided and (ii) to determine the prevalence and incidence of RRT for ESRD due to rare diseases, both overall and separately for children and adults. Methods The Orphanet classification of rare disease was searched for rare diseases potentially causing ESRD, and these diagnosis codes were mapped to the corresponding ERA–EDTA primary renal disease codes. Thirty-one diagnoses were defined as rare diseases causing ESRD. Results From 1 January 2007 to 31 December 2011, 7194 patients started RRT for a rare disease (10.6% children). While some diseases were exclusively found in adults (e.g. Fabry disease), primary oxalosis, cystinosis, congenital anomalies of the kidney and urinary tract (CAKUT) and medullary cystic kidney disease affected young patients in up to 46%. On 31 December 2011, 20 595 patients (12.4% of the total RRT population) were on RRT for ESRD caused by a rare disease. The point prevalence was 32.5 per million age-related population in children and 152.0 in adults. Only 5.8% of these patients were younger than 20 years; however, 57.7% of all children on RRT had a rare disease, compared with only 11.9% in adults. CAKUT and focal segmental glomerulosclerosis were the most prevalent rare disease entities among patients on RRT. Conclusions More than half of all children and one of nine adults on RRT in the ERA–EDTA Registry suffer from kidney failure due to a rare disease, potentially with a large number of additional undiagnosed or miscoded cases. Comprehensive diagnostic assessment and the application of accurate disease classification systems are essential for improving the identification and management of patients with rare kidney diseases. [ABSTRACT FROM AUTHOR]