Management of children with congenital nephrotic syndrome: challenging treatment paradigms

Late nephrectomy in infants with congenital nephrotic syndrome of the Finnish type

AIM

Bilateral nephrectomy is commonly performed in patients with congenital nephrotic syndrome of the Finnish type. The optimal timing of nephrectomy is unclear.

METHODS

Growth, thromboembolic events, infections, transplant-related complications and ability to eat were compared between infants with early (Group 1, n = 13) and late (Group 2, n = 10) nephrectomy. 'Early' was defined as nephrectomy at 7-kg body weight followed by peritoneal dialysis and 'late' as nephrectomy at ≥10 kg followed by 3-4 weeks of haemodialysis and kidney transplantation. Patients were followed until the end of the first post-transplant year.

RESULTS

Dialysis time was significantly longer in group 1 than in group 2. Late nephrectomy did not increase the risk for thromboembolic events or septicaemia but decreased tube feeding dependency (group 1 69% vs. group 2 20%, p = 0.019). Motor development at transplantation was considered normal in 80% of the infants with late nephrectomy compared to 31% in the early nephrectomy group (p = 0.019); however, the difference between the groups disappeared by the end of the follow-up.

CONCLUSION

Infants with late nephrectomy have comparative outcome but less feeding tube dependency and better motor development during the first post-transplant months compared to infants with early nephrectomy.

New insights from the genetic work-up in early onset nephrotic syndrome: report from a registry in western India

BACKGROUND

Eighty-five percent of infants with congenital nephrotic syndrome (CNS) and 66% with infantile NS (INS) are likely to have a monogenic etiology. There exists a significant genetic variability between different regions and ethnic groups. This study aimed to determine the genetic defects in children with CNS and INS by establishing a registry in western India.

METHODS

In this cross-sectional study, pediatric nephrologists from 13 private and government institutions shared relevant clinical data and details of the genetic evaluation of children presenting with NS within the first year of life.

RESULTS

The median age at presentation was 9 months (range 1-23, IQR 3-13 months), history of consanguinity between parents existed in 14 patients (34%), family history of similar illness in 6 (15%), and extra-renal manifestations in 17 (41%). Twenty-five (61%) were confirmed to have a monogenic etiology. NPHS1 gene was the most implicated (9/25) followed by PLCE1 (5/25). There were 12 variants of uncertain significance (VUS) involving 10 genes (10/25, 40%), and no definite genetic abnormality was found in 4 (25%). A re-analysis of these VUS attempted 2-3 years later facilitated reclassification of 7/12 (58%); increasing the diagnostic yield from 61 to 68.2%.

CONCLUSIONS

Consistent with worldwide data, variants in NPHS1 gene were the most common cause of NS in infancy; however, PLCE1 was implicated more frequently in our cohort. NUP93 and COL4A3 were reported in early onset NS for the first time. Reclassification of VUS should be attempted, if feasible, since it may lead to a useful revision of diagnosis.

Native nephrectomy in advanced pediatric kidney disease: indications, timing, and surgical approaches

In pediatric kidney failure, native kidneys may pose a risk to successful transplant outcomes. The indications and timing of native nephrectomy represent a controversial management decision. A lack of high-quality, outcomes-based data has prevented development of evidence-based guidelines for intervention. In this article, we review the published literature on medical indications for native nephrectomy and current knowledge gaps. In addition, we provide a surgical perspective regarding timing and approach.

Genetic stratification reveals COL4A variants and spontaneous remission in Egyptian children with proteinuria in the first 2 years of life

AIM

The earlier the onset of proteinuria, the higher the incidence of genetic forms. Therefore, we aimed to analyse the spectrum of monogenic proteinuria in Egyptian children presenting at age <2 years.

METHODS

The results of 27-gene panel or whole-exome sequencing were correlated with phenotype and treatment outcomes in 54 patients from 45 families.

RESULTS

Disease-causing variants were identified in 29/45 (64.4%) families. Mutations often occurred in three podocytopathy genes: NPHS1, NPHS2 and PLCE1 (19 families). Some showed extrarenal manifestations. Additionally, mutations were detected in 10 other genes, including novel variants of OSGEP, SGPL1 and SYNPO2. COL4A variants phenocopied isolated steroid-resistant nephrotic syndrome (2/29 families, 6.9%). NPHS2 M1L was the single most common genetic finding beyond the age of 3 months (4/18 families, 22.2%). Biopsy results did not correlate with genotypes (n = 30). On renin-angiotensin-aldosterone system antagonists alone, partial and complete remission occurred in 3/24 (12.5%) patients with monogenic proteinuria each, whereas 6.3% (1/16) achieved complete remission on immunosuppression.

CONCLUSION

Genotyping is mandatory to avoid biopsies and immunosuppression when proteinuria presents at age <2 years. Even with such a presentation, COL4A genes should be included. NPHS2 M1L was prevalent in Egyptian children (4 months-2 years) with proteinuria, demonstrating precision diagnostic utility.

A multicenter retrospective study of calcineurin inhibitors in nephrotic syndrome secondary to podocyte gene variants

While 44-83% of children with steroid-resistant nephrotic syndrome (SRNS) without a proven genetic cause respond to treatment with a calcineurin inhibitor (CNI), current guidelines recommend against the use of immunosuppression in monogenic SRNS. This is despite existing evidence suggesting that remission with CNI treatment is possible and can improve prognosis in some cases of monogenic SRNS. Herein, our retrospective study assessed response frequency, predictors of response and kidney function outcomes among children with monogenic SRNS treated with a CNI for at least three months. Data from 203 cases (age 0-18 years) were collected from 37 pediatric nephrology centers. Variant pathogenicity was reviewed by a geneticist, and 122 patients with a pathogenic and 19 with a possible pathogenic genotype were included in the analysis. After six months of treatment and at last visit, 27.6% and 22.5% of all patients respectively, demonstrated partial or full response. Achievement of at least partial response at six months of treatment conferred a significant reduction in kidney failure risk at last follow-up compared to no response (hazard ratio [95% confidence interval] 0.25, [0.10-0.62]). Moreover, risk of kidney failure was significantly lower when only those with a follow-up longer than two years were considered (hazard ratio 0.35, [0.14-0.91]). Higher serum albumin level at CNI initiation was the only factor related to increased likelihood of significant remission at six months (odds ratio [95% confidence interval] 1.16, [1.08-1.24]). Thus, our findings justify a treatment trial with a CNI also in children with monogenic SRNS.

Childhood nephrotic syndrome and the clinical profile of thromboembolism: a systematic review and meta-analysis

Nephrotic syndrome (NS) is a common kidney disease of childhood, affecting 2-7 children per 100,000. A potentially life-threatening complication affecting children with NS is thromboembolism (TE). However, there remains a paucity of information regarding the burden of TE and its associated risk factors in this population. A systematic review was performed on observational studies examining TE events in children with NS, published in Medline, Embase, CINAHL, and CENTRAL, until May 2021. Meta-analyses were separately conducted on the prevalence of TE within articles exclusively studying children with congenital NS and among articles including all forms of NS. Out of 13,626 articles, 22 were included (14,290 children). The pooled prevalence of symptomatic TE among articles including patients with all forms of NS was 3.60% (95% CI 1.95-5.63), which increased to 8.70% (95% CI 5.11-12.96) in articles with exclusively congenital NS patients. Children with steroid-resistant NS were at a higher risk of TE compared to steroid-sensitive children (OR 4.40, 95% CI 1.34-15.59, p = 0.013). Focal segmental glomerulosclerosis was the most common histology present in patients with TE (51.2%). Children diagnosed with NS have a significant risk of TE, particularly in patients with congenital NS and steroid resistance. IMPACT: The prevalence of symptomatic thromboembolic (TE) events in children with nephrotic syndrome (NS) was 3.60% (95% CI 1.95-5.63), which increased more than two-fold in children with congenital NS to 8.70% (95% CI 5.11-12.96). Potential risk factors for TE events in this population include congenital forms of NS and steroid resistance. This review provides a better estimate of the prevalence of TE in children with NS, while identifying potentially higher-risk populations who may benefit from TE screening and thromboprophylaxis.

Congenital Nephrotic Syndrome of the Finnish Type in a Dominican Newborn: An Overview and Case Report

Congenital nephrotic syndrome of the Finnish type (CNS-FT) is a rare genetic condition that causes massive proteinuria, hypoproteinemia, hypercholesterolemia, and edema that progresses to end-stage renal disease. Symptoms may manifest in utero as fetal hydrops or during the first few days to months of life. This article shares the case of a Dominican infant who presented with CNS-FT. It provides a comprehensive overview of CNS-FT including the underlying genetic cause, prenatal and postnatal diagnostic testing options, and treatment recommendations. It walks the reader through the diagnostic and initial and longer-term management of this infant and provides patient outcome at 10 months of age.

Clinical presentation and management of nephrotic syndrome in the first year of life: A report from the Pediatric Nephrology Research Consortium

BACKGROUND AND OBJECTIVES

Nephrotic syndrome (NS) in the first year of life is called congenital (CNS) if diagnosed between 0-3 months, or infantile (INS) if diagnosed between 3-12 months of age. The aim of this study was to determine if there were clinically meaningful differences between CNS and INS patients, regarding clinical presentation, management and outcomes.

DESIGN SETTING PARTICIPANTS AND MEASUREMENTS

Eleven Pediatric Nephrology Research Consortium sites participated in the study, using IRB-approved retrospective chart reviews of CNS and INS patients born between 1998 and 2019. Data were collected on patient characteristics, pertinent laboratory tests, provided therapy, timing of unilateral/bilateral nephrectomy and initiation of renal replacement therapy (RRT).

RESULTS

The study included 69 patients, 49 with CNS and 20 with INS, with a median age at diagnosis of 1 and 6 months, respectively. Management for the two groups was similar regarding nutrition, thyroxin supplementation, immunoglobulin administration, and thrombosis prophylaxis. Within the first 2 months after diagnosis, daily albumin infusions were used more often in CNS vs. INS patients (79 vs. 30%; p = 0.006), while weekly infusions were more common in INS patients (INS vs. CNS: 50 vs. 3%; p = 0.001). During the 6 months preceding RRT, albumin infusions were more frequently prescribed in CNS vs. INS (51 vs. 15%; p = 0.007). Nephrectomy was performed more often in CNS (78%) than in INS (50%; p = 0.02). End-stage kidney disease tended to be more common in children with CNS (80%) vs. INS (60%; p = 0.09).

CONCLUSION

Compared to INS, patients with CNS had a more severe disease course, requiring more frequent albumin infusions, and earlier nephrectomy and RRT. Despite center-specific variations in patient care, 20-40% of these patients did not require nephrectomy or RRT.

Congenital nephrotic syndrome

Congenital nephrotic syndrome (CNS), a challenging form of nephrotic syndrome, is characterized by massive proteinuria, hypoalbuminemia, and edema. Extensive leakage of plasma proteins is the main feature of CNS. Patients can be diagnosed in utero or during the first few weeks of life, usually before three months. The etiology of CNS can be related to either genetic or nongenetic etiologies. Pathogenic variants in NPHS1, NPHS2, LAMB2, WT1, and PLCE1 genes have been implicated in this disease. The clinical course is complicated by significant edema, infections, thrombosis, hypothyroidism, failure to thrive, and others. Obtaining vascular access, frequent intravenous albumin infusions, diuretic use, infection prevention, and nutritional support are the mainstay management during their first month of life. The best therapy for these patients is kidney transplantation. CNS diagnosis and treatment continue to be a challenge for clinicians. This review increases the awareness about the pathogenesis, diagnosis, and management of CNS patients.

Genetic Variations and Clinical Features of NPHS1-Related Nephrotic Syndrome in Chinese Children: A Multicenter, Retrospective Study

Introduction: Few studies have addressed the genetic spectrum of NPHS1 variants in Chinese children with nephrotic syndrome. In this multicenter study, the clinical manifestations and features of NPHS1 variants in Chinese children with nephrotic syndrome were researched. Method: Genotypical and phenotypical data from 30 children affected by NPHS1 variants were collected from a multicenter registration system in China and analyzed retrospectively. Results: The patients were divided into two groups: congenital nephrotic syndrome (CNS [n = 24]) and non-CNS (early onset nephrotic syndrome [n = 6]). Renal biopsy was performed on four patients in the non-CNS group, revealing minimal change disease in three and focal segmental glomerulosclerosis in one. A total of 61 NPHS1 variants were detected, involving 25 novel variants. The "recurrent variants" included c.928G>A(p.Asp310Asn) in eight patients with CNS, followed by c.616C>A(p.Pro206Thr) in four, and c.2207T>C (p.Val736Ala) in three. Steroid treatment was applied in 29.2% (7/24)of the patients in the CNS group and 50% (3/6) of the patients in the non-CNS group. One patient in each group experienced complete remission but relapsed subsequently. Immunosuppressants were administered to three patients in the non-CNS group, eliciting an effective response. In the CNS group, three patients underwent renal transplantation and six died mainly from infection. Conclusion: Variants of NPHS1 cause CNS and early childhood-onset nephrotic syndrome. NPHS1 variants in Chinese individuals with nephrotic syndrome (NS) were mainly compound heterozygous variants, and c.928G>A(p.Asp310Asn) in exon 8 may act as a recurrent variant in the Chinese population, followed by c.616C>A(p.Pro206Thr) in exon 6. Steroids and immunosuppressants may be effective in selected patients.

Unilateral nephrectomy for young infants with congenital nephrotic syndrome of the Finnish type

BACKGROUND

The management of congenital nephrotic syndrome of the Finnish type (CNF) is challenging. It is difficult to withdraw intravenous albumin infusions, resulting in long-term hospitalization. In addition, fatal hypotension after bilateral nephrectomy has been reported. In our center, we have performed unilateral nephrectomy during early infancy.

METHODS

Infants diagnosed with CNF between 2011 and 2020 in our institution were enrolled. We examined the clinical course before and after unilateral nephrectomy and evaluated the effectiveness of this strategy.

RESULTS

Seven patients (all showing NPHS1 mutations) were enrolled. All required daily intravenous albumin infusion via central venous catheter (CVC). Unilateral nephrectomy was performed at a median of 76 days of age (59-208 days). Surgical complications did not occur in any of patients. The mean albumin dose was decreased after unilateral nephrectomy (2.0 vs 0.4 g/kg/day; p = 0.02). Intravenous albumin infusion could be withdrawn at a median of 17 days, the CVC removed at a median of 21 days, and they discharged at a median of 82 days after unilateral nephrectomy. Although bacterial infections were noted seven times before unilateral nephrectomy, only one episode occurred after surgery. Four patients initiated peritoneal dialysis at two to three years of age and all of them underwent kidney transplantation thereafter.

CONCLUSIONS

Unilateral nephrectomy during early infancy may be an effective treatment allowing for withdrawal from albumin infusion, prevention of complications, withdrawal from CVCs and shortening hospital stay for patients with CNF.

Skimmed breast milk for treatment of hypertriglyceridemia in an infant with congenital nephrotic syndrome

Congenital nephrotic syndrome (CNS) is a complex condition that requires multidisciplinary care. Hyperlipidemia is a characteristic feature with elevation of serum cholesterol and triglycerides. Little evidence is available to guide treatment of dyslipidemia in infants with CNS. We describe successful treatment of severe hypertriglyceridemia through dietary changes in a boy with CNS. A 9-day-old boy presented to the emergency department with lower extremity edema caused by deep venous thrombosis. Laboratory evaluation identified hypoalbuminemia, nephrotic-range proteinuria, and a pathogenic variant of the NPHS1 gene. The initial triglyceride concentration of 369 mg/dl increased to 3096 mg/dl by 5 weeks of age, when his diet consisted of breast milk. Refrigerated breast milk was skimmed by removing the top layer after allowing it to separate for 24 h. This process was repeated prior to use. Skimmed breast milk was supplemented with medium-chain triglyceride oil and an infant protein powder. After 2 days, the triglyceride concentration declined to 481 mg/dl and, by day 10, to 148 mg/dl. When breast milk supply decreased, a 1:1 ratio of skimmed maternal breast milk to an elemental, very low-fat formula was utilized. The triglyceride concentration remained below 400 mg/dl for the first year of life, except when skimmed breast milk was not available during hospitalization. Severe hypertriglyceridemia caused by CNS can present in the neonatal period and be difficult to manage. In our patient, skimmed maternal breast milk was successful in reducing the triglyceride concentration and should be considered a therapeutic option for children with hyperlipidemia caused by CNS.

Five-Year Follow-Up and Successful Kidney Transplantation in a Girl with a Severe Phenotype of Pierson Syndrome

Pierson syndrome (PIERSS) is a rare autosomal recessive disorder characterized by the combination of congenital nephrotic syndrome (CNS) and extrarenal symptoms including ocular malformations and neurodevelopmental deficits. PIERSS is caused by biallelic pathogenic variants in the LAMB2 gene leading to the defects of β2-laminin, the protein mainly expressed in the glomerular basement membrane, ocular structures, and neuromuscular junctions. Severe complications of PIERSS lead to the fatal outcome in early childhood in majority of the cases. We report a case of 5-year-old girl with severe phenotype of PIERSS caused by biallelic functional null variants of the LAMB2 gene. Due to consequences of CNS, the patient required bilateral nephrectomy and peritoneal dialysis since early infancy. The course was additionally complicated by tubulopathy, life-threatening infections, severe hypertension, erythropoietin-resistant anemia, generalized muscular hypotonia, neurogenic bladder, profound neurodevelopmental delay, epilepsy, gastrointestinal problems, secondary hypothyroidism, and necessity of repeated ocular surgery due to microcoria, cataract, and nystagmus. Due to multidisciplinary efforts, at the age of 4 years, the kidney transplantation was possible. Currently, the renal graft has an excellent function; however, the girl presents severe neurodevelopmental delay. The report presents a unique long-term follow-up of severe PIERSS with a few new phenotypical findings. It highlights the clinical problems and challenges in management of this rare condition.

Management of congenital nephrotic syndrome: consensus recommendations of the ERKNet-ESPN Working Group

Congenital nephrotic syndrome (CNS) is a heterogeneous group of disorders characterized by nephrotic-range proteinuria, hypoalbuminaemia and oedema, which manifest in utero or during the first 3 months of life. The main cause of CNS is genetic defects in podocytes; however, it can also be caused, in rare cases, by congenital infections or maternal allo-immune disease. Management of CNS is very challenging because patients are prone to severe complications, such as haemodynamic compromise, infections, thromboses, impaired growth and kidney failure. In this consensus statement, experts from the European Reference Network for Kidney Diseases (ERKNet) and the European Society for Paediatric Nephrology (ESPN) summarize the current evidence and present recommendations for the management of CNS, including the use of renin-angiotensin system inhibitors, diuretics, anticoagulation and infection prophylaxis. Therapeutic management should be adapted to the clinical severity of the condition with the aim of maintaining intravascular euvolaemia and adequate nutrition, while preventing complications and preserving central and peripheral vessels. We do not recommend performing routine early nephrectomies but suggest that they are considered in patients with severe complications despite optimal conservative treatment, and before transplantation in patients with persisting nephrotic syndrome and/or a WT1-dominant pathogenic variant.

Thromboprophylaxis in congenital nephrotic syndrome: 15-year experience from a national cohort

INTRODUCTION

Congenital nephrotic syndrome (CNS) is an ultra-rare disease associated with a pro-thrombotic state and venous thromboembolisms (VTE). There is very limited evidence evaluating thromboprophylaxis in patients with CNS. This study aimed to determine the doses and duration of treatment required to achieve adequate thromboprophylaxis in patients with CNS.

METHODS

From 2005 to 2018 children in Scotland with a confirmed genetic or histological diagnosis of CNS were included if commenced on thromboprophylaxis. The primary study endpoint was stable drug monitoring. Secondary outcomes included VTE or significant haemorrhage.

RESULTS

Eight patients were included; all initially were commenced on low-molecular weight heparin (enoxaparin). Four patients maintained therapeutic anti-Factor Xa levels (time 3-26 weeks, dose 3.2-5.07 mg/kg/day), and one patient developed a thrombosis (Anti-Factor Xa: 0.27 IU/ml). Four patients were subsequently treated with warfarin. Two patients maintained therapeutic INRs (time 6-11 weeks, dose 0.22-0.25 mg/kg/day), and one patient had two bleeding events (Bleed 1: INR 6, Bleed 2: INR 5.5).

CONCLUSIONS

Achieving thromboprophylaxis in CNS is challenging. Similar numbers of patients achieved stable anticoagulation on warfarin and enoxaparin. Enoxaparin dosing was nearly double the recommended starting doses for secondary thromboprophylaxis. Bleeding events were all associated with supra-therapeutic anticoagulation.

Fungal peritonitis in children on peritoneal dialysis at a tertiary care Centre

BACKGROUND

Fungal peritonitis (FP) is an infrequent but serious complication in children undergoing peritoneal dialysis (PD). This study aimed to explore the risk factors, clinical manifestations, causative organisms, fungal susceptibility findings, and outcomes of FP in children from Saudi Arabia.

METHODS

In this case-control study, the medical records and laboratory results of paediatric patients aged 0-14 years who underwent PD were reviewed for FP episodes. All FP episodes were matched with PD-related bacterial peritonitis episodes (1:4 ratio).

RESULTS

A total of 194 episodes of PD-related peritonitis occurred between 2007 and 2017, among which 11 were FP episodes (5.6%), representing a rate of 0.03 episodes per patient-year. Of these 11 episodes, 9 were caused by Candida species (82%). Compared with the bacterial peritonitis group, the FP group had a higher proportion of patients with congenital/infantile nephrotic syndrome (p = 0.005) and those younger than 5 years of age (p = 0.001). We observed a higher rate of catheter removal in the FP group than in the bacterial peritonitis group (p <  0.001); however, 1 patient died despite catheter removal. Moreover, 75% of Candida species isolates were susceptible to fluconazole.

CONCLUSIONS

This study revealed that FP is associated with a significant risk of peritoneal membrane failure among children undergoing PD. Therefore, early diagnosis and prompt management are essential. We also found that congenital/infantile nephrotic syndrome and young age (5 years old or younger) were risk factors for FP in children undergoing PD.

Congenital Nephrotic Syndrome With a Novel Presentation in Saudi Arabia

Congenital nephrotic syndrome (CNS) is a rare and serious entity of renal diseases diagnosed in infants younger than three months. The triad of this syndrome is proteinuria, hypoalbuminemia, and edema. Without renal transplantation, these patients rarely live beyond the age of three years. Infections and sepsis are the most common causes of this condition among children. The majority of patients progress to end-stage renal disease early in life, even with aggressive supportive therapy. In this study, we present a case of a 10-year-old Saudi boy who had been diagnosed with CNS since he was two months old and has improved without renal transplantation.

Clinical utility of ultra-rapid whole-genome sequencing in an infant with atypical presentation of WT1-associated nephrotic syndrome type 4

Relatively little is known about phenotypic variability in nonsyndromic nephropathy associated with the gene encoding the WT1 transcription factor. We report a 12-mo-old female who presented with vomiting, diarrhea, and fatigue in the setting of renal failure and malignant hypertension. Trio ultra-rapid whole-genome sequencing identified a novel, likely pathogenic, de novo missense variant (c.485T > A, p.Val162Asp) in WT1 in 46 h, consistent with a diagnosis of nephrotic syndrome type 4 (NPHS4; OMIM 256370). This disorder typically presents with nephrotic syndrome (gross proteinuria, hypoalbuminemia, and edema). Rapid diagnosis had an immediate impact on her clinical management in the pediatric intensive care unit. Diagnostic renal biopsy was avoided, and placement of permanent dialysis access, a gastrostomy tube, and bilateral nephrectomy were accelerated. This report expands the presenting phenotype of nonsyndromic nephrotic syndrome and/or renal failure due to heterozygous variants in WT1 (NPHS4). It also highlights the relationship between time to genomic diagnosis and clinical utility in critically ill infants.

Congenital nephrotic syndrome: is early aggressive treatment needed? Yes

Congenital nephrotic syndrome (CNS) was primarily considered one disease entity. Hence, one treatment protocol was proposed in the beginning to all CNS patients. Today, with the help of gene diagnostics, we know that CNS is a heterogeneous group of disorders and therefore, different treatment protocols are needed. The most important gene defects causing CNS are NPHS1, NPHS2, WT1, LAMB2, and PLCE1. Before active treatment, all infants with CNS died. It was stated already in the mid-1980s that intensive medical therapy followed by kidney transplantation (KTx) should be the choice of treatment for infants with severe CNS. In Finland, early aggressive treatment protocol was adopted from the USA and further developed for treatment of children with the Finnish type of CNS. The aim of this review is to state reasons for "early aggressive treatment" including daily albumin infusions, intensified nutrition, and timely bilateral nephrectomy followed by KTx at the age of 1-2 years.

Home Albumin Infusion Therapy, Another Alternative Treatment in Patients With Congenital Nephrotic Syndrome of the Finnish Type

Background: Congenital nephrotic syndrome of the Finnish type (CNF) is a rare, severe glomerular disease caused by mutations in the NPHS1 gene, which codes for nephrin. It is characterised by massive proteinuria and severe edoema. Progression to end-stage kidney failure occurs during early childhood and the only curative treatment is kidney transplantation. Nowadays, patients need aggressive medical treatment, which includes daily albumin infusions (for months) until they get clinical stability to receive transplant. Objective: In our paediatric hospital, we implemented a multidisciplinary program for the home infusion of albumin with outpatient follow-up. The aim of the study was to assess the safety and efficacy of this program for the first four years of its implementation. Material and Methods: Retrospective observational study of CNF paediatric patients treated with home albumin infusion therapy from March 2014 to July 2018 at a tertiary care paediatric hospital. Information on albumin administration was obtained from the electronic prescription assistance program and details on clinical and care-related variables from the hospital's electronic information systems. Results: Four patients with CNF received albumin infusions for 18, 21, 22 months, and 3 years. The treatment was safe, and the complication rates were to be expected considering the severity of disease. Patients required a median of two hospital admissions a year (19 in total); 47% due to catheter-related complications, but there were just three catheter infections. Conclusions: In our experience, home albumin infusion therapy is safe and effective and helps to improve children health and quality of life.

Diagnostic and Management Challenges in Congenital Nephrotic Syndrome

Congenital Nephrotic Syndrome (CNS) is defined as nephrotic range proteinuria, hypoalbuminaemia and edema in the first three months of life. CNS is most commonly genetic in cause, with international variance in the incidence of causative mutations. Initially defined by the histopathological appearance, increasingly sophisticated and accessible genetic analyses now provide a body of evidence to suggest that there is a disparity between the histological appearance, the genotype of individuals and the severity of the clinical disease. Through the evolution of management approaches CNS has changed from being an invariably fatal condition to one with appreciable ongoing morbidity and mortality but comparably good outcomes to other causes of paediatric end-stage renal disease, especially following transplantation. This review briefly summarises the more commonly recognised genetic mutations leading to CNS, addresses common management decisions, and concludes with potential therapies for the future.

Early or Late Transplantation in Congenital Nephrotic Syndrome: Which is Effective for Optimal Growth?

Congenital nephrotic syndrome (CNS) is a genetic disease that is present in the antenatal period or during the first 3 months of life. In this study, we aimed to compare growth parameters of patients with CNS who received kidney transplants and either (1) had a normal glomerular filtration rate (GFR) at the time of transplant or (2) chronic kidney disease (CKD) at the time of transplant. Patients with a diagnosis of CNS who had a minimum follow-up period of 6 months were evaluated retrospectively. Children at stages 4 or 5 CKD or patients receiving dialysis during the pretransplant period were defined as group 1; patients with normal GFR at the time of transplantation were classified as group 2. Short stature and low weight were defined as less than -2 standard deviation scores (SDS) for height and weight according to their age. A total of 17 patients were included in the study. Thirteen of 17 patients had NPHS1 gene mutations. Group 1 and group 2 consisted of 8 and 9 patients, respectively. Mean height SDS and mean weight SDS in group 2 were higher than group 1 in the pretransplant period (-4.34 ± 1.74 vs -2.84 ± 1.56; P = .011 and -3.54 ± 0.93 vs -1.83 ± 1.13; P = .008). In the post-transplant period, the significant difference in height SDS continued in favor of group 2 (-3.16 ± 1.11 vs -1.16 ± 0.87; P = .002). The short stature rate was 83% in group 1 and 72% in group 2 in the pretransplant period (P = .62), and 83% in group 1 and 27% in group 2 in the post-transplant period (P = .02). Early renal transplantation seems to be effective for optimal height gain in children with CNS.

Infants with congenital nephrotic syndrome have comparable outcomes to infants with other renal diseases

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.