Renal Involvement in 2 Siblings With Cockayne Syndrome

Renal involvement in Cockayne syndrome is rare and its pathogenesis is yet unknown. We report herein 2 cases (siblings) with Cockayne syndrome type A confirmed by biochemical and molecular assays. The first case was a 13-year-old girl who presented with nephritic syndrome and a rapidly progressive kidney failure. Her younger sister, 7 years old, exhibited hypertension, hyperfiltration, and microalbuminuria. She had hyperreninemia and hyperaldosteronemia without kidney failure or renal arterial stenosis. Renal biopsy, performed the older sister, revealed cystic focal segmental glomerulosclerosis, arteriosclerosis, tubulointerstitial fibrosis, and tubular atrophy. The different clinical phenotypes in the two siblings support the absence of an obvious genotype-phenotype correlation in Cockayne syndrome type A patients. In the older sister, the particular focal glomerular sclerosis and senile lesions assume that kidney disease in Cockayne syndrome may be related to prematurely aging secondary to a defective nucleotide repair.

[SYSTEMIC LUPUS ERYTHEMATOSUS WITH LUPUS NEPHRITIS IN THE ELDERLY (CLINICAL OBSERVATION)]

We report a clinical case of SLE in a women affected at the age of 63 years who had recurrent nephrotic syndrome with the development of renal insufficiency at the onset and a good outcome of therapy with a large total dose cyclophosphamide.

Recurrent Nephrotic Syndrome After Renal Transplant in Children

OBJECTIVES

Recurrent disease occurs in around 30% of children transplanted for steroid-resistant nephrotic syndrome. Its precipitating risk factors have rarely been studied in the Middle East. The aim of our study was to determine what characterizes posttransplant recurrence of nephrotic syndrome in Syrian children.

MATERIALS AND METHODS

We performed a retrospective analysis of 12 nephrotic children who received 1 renal allograft at the Kidney Hospital in Damascus from 2002 to 2013.

RESULTS

Native kidney biopsy results showed focal segmental glomerulosclerosis in 9 of 10 patients. Four patients had 1 or more sibling affected with nephrotic syndrome, and the remaining patients were labeled as having sporadic disease. Genetic screening for NPHS2, NPHS1, and Wilms tumor gene (WT1) mutations were done for 6 patients, and 1 novel homozygous NPHS2 mutation was identified in 1 patient. All patients received transplants from living donors. Four patients had recurrence of initial disease after transplant (overall recurrence rate of 33%). However, 1 patient showed complete and spontaneous remission 20 months after transplant; As expected, the patient with NPSH2 mutation had no recurrence. Patients with sporadic disease showed risk of recurrence 5 times higher than patients with familial disease (P = .24). Interestingly, all recurrent cases had received a kidney from a related donor and were initially classified as having sporadic disease. Although not statistically significant, the risk of recurrence from related donor grafts was 6.75 times higher than from unrelated donors (P = .16). To the best of our knowledge, this observation, the first of its kind, has never been investigated or pointed out in the literature.

CONCLUSIONS

Further research is needed to confidently determine whether living related donor grafts are associated with increased incidence of recurrence of nephrotic syndrome.

Recurrent Nephrotic Syndrome After Renal Transplant in Children

OBJECTIVES

Recurrent disease occurs in around 30% of children transplanted for steroid-resistant nephrotic syndrome. Its precipitating risk factors have rarely been studied in the Middle East. The aim of our study was to determine what characterizes posttransplant recurrence of nephrotic syndrome in Syrian children.

MATERIALS AND METHODS

We performed a retrospective analysis of 12 nephrotic children who received 1 renal allograft at the Kidney Hospital in Damascus from 2002 to 2013.

RESULTS

Native kidney biopsy results showed focal segmental glomerulosclerosis in 9 of 10 patients. Four patients had 1 or more sibling affected with nephrotic syndrome, and the remaining patients were labeled as having sporadic disease. Genetic screening for NPHS2, NPHS1, and Wilms tumor gene (WT1) mutations were done for 6 patients, and 1 novel homozygous NPHS2 mutation was identified in 1 patient. All patients received transplants from living donors. Four patients had recurrence of initial disease after transplant (overall recurrence rate of 33%). However, 1 patient showed complete and spontaneous remission 20 months after transplant; As expected, the patient with NPSH2 mutation had no recurrence. Patients with sporadic disease showed risk of recurrence 5 times higher than patients with familial disease (P = .24). Interestingly, all recurrent cases had received a kidney from a related donor and were initially classified as having sporadic disease. Although not statistically significant, the risk of recurrence from related donor grafts was 6.75 times higher than from unrelated donors (P = .16). To the best of our knowledge, this observation, the first of its kind, has never been investigated or pointed out in the literature.

CONCLUSIONS

Further research is needed to confidently determine whether living related donor grafts are associated with increased incidence of recurrence of nephrotic syndrome.

Characteristics of patients diagnosed with renal vein thrombosis and glomerulopathy: a case series

BACKGROUND

Few contemporary studies have evaluated the clinical characteristics of patients with biopsy-proven glomerulopathy diagnosed with renal vein thrombosis (RVT).

METHODS

Retrospective case series study within an integrated health system in a 12-year period (January 1, 2000 through December 31, 2011) investigating clinical characteristics of all adult patients who underwent native or transplant kidney biopsy and also had a diagnosis of RVT. Patient characteristics, diagnostic studies, and outcomes were evaluated.

RESULTS

Among 3763 eligible patients, 17 had imaging confirmed RVT. Of these, 15 had membranous nephropathy (idiopathic or secondary to autoimmune disease). Although the biopsy population included primary and secondary glomerular disease patients, all 17 RVT patients had severe nephrotic syndrome and profound hypoalbuminemia with mean (SD) of albumin: 1.5 g/dL (0.66).

CONCLUSION

Clinically significant RVT in patients with glomerulopathy appears to be a rather rare entity, occurring predominantly in patients with severe nephrotic syndrome due to idiopathic membranous nephropathy and membranous nephropathy secondary to autoimmune disease.

Platelet abnormalities in nephrotic syndrome

Nephrotic syndrome (NS) is a common kidney disease associated with a significantly increased risk of thrombotic events. Alterations in plasma levels of pro- and anti-coagulant factors are involved in the pathophysiology of venous thrombosis in NS. However, the fact that the risk of both venous and arterial thrombosis is elevated in NS points to an additional role for blood platelets. Increased platelet counts and platelet hyperactivity have been observed in nephrotic children. Platelet hyperaggregability, increased release of active substances, and elevated surface expression of activation-dependent platelet markers have been documented. The mechanisms underlying those platelet alterations are multifactorial and are probably due to changes in plasma levels of platelet-interfering proteins and lipid changes, as a consequence of nephrosis. The causal relationship between platelet alterations seen in NS and the occurrence of thromboembolic phenomena remains unclear. Moreover, the efficiency of prophylactic treatment using antiplatelet agents for the prevention of thrombotic complications in nephrotic patients is also unknown. Thus, antiplatelet medication is currently not generally recommended for routine prophylactic therapy.

PATTERN AND OUTCOME OF RENAL DISEASES IN HOSPITALIZED CHILDREN IN TIKUR ANBESSA SPECIALIZED TEACHING HOSPITAL, ADDIS ABABA, ETHIOPIA

BACKGROUND

Renal diseases are major causes of morbidity and mortality in pediatric practice. Pediatric patients with renal disease, especially younger ones may present with nonspecific signs and symptoms unrelated to the urinary tract. Unexplained fever or failure to thrive may be the only manifestation. Most children with renal diseases in our hospital arrive very late either because of inadequate health awareness among the parents or failure of recognizing the symptoms of renal diseases at a lower health care level. This review will highlight the symptoms of renal diseases at presentation and outcomes of treatment in children in a major referral hospital.

METHODS

A cross-sectional retrospective chart review was done over a period of 3 years (June, 2012 to May, 2015) in 381 admitted children (Birth-17 years) at Tikur Anbessa Specialized Teaching Hospital in Addis Ababa, Ethiopia.

RESULTS

Out of 14521 pediatric ward admissions in the study period, kidney diseases accounted for 473 admissions in 381 children, accounting for 3.3% of all admissions. The three most common renal diseases observed were congenital anomalies of the kidney and urinary tract (CAKUT) seen in 127 children (26.8%), followed by nephrotic syndrome in 80 children 16.9% and acute glomerulonephritis in 58 children (12.2%). Other renal diseases observed were urinary tract infection 8.0%, urolithiasis 6.7%, Wilm’s tumor 6.3%, acute kidney injury 4.2% and chronic kidney disease 4.0%. Other less frequently detected diseases were bladder exstrophy, lupus nephritis, Henock shonlein Purpura nephritis and prune-belly syndrome. Out of 381 children 207 (54.3%) recovered normal renal function, 20(5.2%) remained with proteinuria, 13(3.4%) progressed to chronic kidney disease and 11(2.9%) died. Sixty one nephrotic children (76.3%) achieved remission but 17 children (21.3%) remained with proteinuria; one steroid resistant child died of end stage renal disease. Ten children (2.6%) with different renal diseases were lost to follow-up and 5 (1.3%) discharged against medical advice.

CONCLUSIONS

This data reflects that many of the renal diseases are preventable or potentially curable. Therefore, improvement of pediatric renal services and training of health workers would help in early detection and treatment of these conditions leading to reduction in their morbidity and mortality.

[Management of patients with nephrotic syndrome]

Nephrotic syndrome is a group of clinical symptoms and laboratory findings, caused by heavy proteinuria, which may be caused by many glomerular diseases. In the approach to a patient with nephrotic syndrome is important to establish an aetiology of the disease, with excluding its secondary causes and in most cases with renal biopsy. The treatment aims to prevent or slow further kidney damage. It involves addressing the underlying medical condition and the treatment of symptoms such as edema, proteinuria, hyperlipidemia, as well as preventing complications like thromboembolic disease, infections or undernutrition.

Body weight changes in children with idiopathic nephrotic syndrome

BACKGROUND

Aim of the study was to evaluate factors affecting body mass change in children with idiopathic nephrotic syndrome (INS) during 6-months treatment of initial disease bout with glucocorticoids (GC).

MATERIAL AND METHODS

We studied 31 children with INS (22♂, 9♀, 3.6±1.8 years) treated during 6 months with GC due to initial INS bout and 31 control healthy children (18♂, 13♀, 4.0±1.8 years). Following factors were evaluated: body mass, body mass index (BMI), BMI Z-score, gender, age, gestational age at birth, birth weight, GC dose, parental age and BMI, time spent for TV/computer, physical activity, place of residence.

RESULTS

Mean initial BMI Z-score was 0.35±1.1 in children with INS and -0.11±1.5 in the control group, after 6 months 0.8±1.2 (P=0.049) and 0.07±1.5 (P=0.629), respectively. Δ0-6 BMI Z-score correlated with initial BMI Z-score (r=-0.45, P=0.001), maternal age (r=0.38, P=0.04), and paternal BMI (r=0.51, P=0.0037).

CONCLUSIONS

1. Initial 6-month GC therapy may result in body mass increase in children with INS. 2. Risk factors for body mass increase in children with INS during the first 6 months of therapy include low initial BMI, older maternal age and paternal obesity.

[Idiopathic Nephrotic Syndrome: recommendations of the Nephrology Branch of the Chilean Society of Pediatrics. Part One]

Idiopathic nephrotic syndrome is the most common glomerular disease in childhood, affecting 1 to 3 per 100,000 children under the age of 16. It most commonly occurs in ages between 2 and 10. Its cause is unknown and its histology corresponds to minimal change disease in 90% of cases, or focal segmental glomerulosclerosis. 80 to 90% of cases respond to steroids (steroid-sensitive nephrotic syndrome) with good prognosis and long-term preservation of renal function over time. 70% of patients with SSNS have one or more relapses in their evolution, and of these, 50% behave as frequent relapsing or steroid-dependent, a group that concentrate the risk of steroid toxicity. Patients with steroid-resistant nephrotic syndrome have a poor prognosis and 50% of them evolve to end-stage renal disease. The goal of therapy is to induce and maintain remission of the disease, reducing the risk secondary to proteinuria while minimizing the adverse effects of treatments, especially with prolonged use of corticosteroids. This paper is the result of the collaborative effort of the Nephrology Branch of the Chilean Society of Pediatrics with aims at helping pediatricians and pediatric nephrologists to treat pediatric SNI. In this first part, recommendations of steroid-sensitive nephrotic syndrome are discussed.

Bioimpedance for assessing volume status in children with nephrotic syndrome

BACKGROUND/AIM

The effectiveness of assessing volume load via bioimpedance in pediatric patients with nephrotic syndrome (NS) was investigated.

MATERIALS AND METHODS

Patients with NS (n = 34) were compared with healthy controls (n = 20). The inferior vena cava index and inferior vena cava collapsibility index (IVCCI) scores were determined for all subjects. Bioimpedance measurements were used to directly determine volume load. Clinical findings, relative fluid load, and echocardiographic measurements were determined and compared with bioimpedance in calculating volume load.

RESULTS

The sensitivity and specificity of bioimpedance in determining volume load were found to be 65% and 90%, respectively. IVCCI was lower in NS patients than in controls. There were also significant differences in IVCCI values between patients with localized and generalized edema. Relative fluid load was higher in NS patients with generalized edema as opposed to patients with localized edema. For calculating volume load, the sensitivity of bioimpedance, clinical findings, and echocardiographic measurements was 87%, 95%, and 83%, respectively, whereas the specificity of determining volume load by bioimpedance, clinical findings, and echocardiographic measurements was 50%, 10%, and 80%, respectively.

CONCLUSION

Our data suggest that bioimpedance may be superior to echocardiography in determining volume load in children with NS, because it is cost-effective, reliable, and relatively simple to perform.

Proteinuria Increases Plasma Phosphate by Altering Its Tubular Handling

Proteinuria and hyperphosphatemia are cardiovascular risk factors independent of GFR. We hypothesized that proteinuria induces relative phosphate retention via increased proximal tubule phosphate reabsorption. To test the clinical relevance of this hypothesis, we studied phosphate handling in nephrotic children and patients with CKD. Plasma fibroblast growth factor 23 (FGF-23) concentration, plasma phosphate concentration, and tubular reabsorption of phosphate increased during the proteinuric phase compared with the remission phase in nephrotic children. Cross-sectional analysis of a cohort of 1738 patients with CKD showed that albuminuria≥300 mg/24 hours is predictive of higher phosphate levels, independent of GFR and other confounding factors. Albuminuric patients also displayed higher plasma FGF-23 and parathyroid hormone levels. To understand the molecular mechanisms underlying these observations, we induced glomerular proteinuria in two animal models. Rats with puromycin-aminonucleoside-induced nephrotic proteinuria displayed higher renal protein expression of the sodium-phosphate co-transporter NaPi-IIa, lower renal Klotho protein expression, and decreased phosphorylation of FGF receptor substrate 2α, a major FGF-23 receptor substrate. These findings were confirmed in transgenic mice that develop nephrotic-range proteinuria resulting from podocyte depletion. In vitro, albumin did not directly alter phosphate uptake in cultured proximal tubule OK cells. In conclusion, we show that proteinuria increases plasma phosphate concentration independent of GFR. This effect relies on increased proximal tubule NaPi-IIa expression secondary to decreased FGF-23 biologic activity. Proteinuria induces elevation of both plasma phosphate and FGF-23 concentrations, potentially contributing to cardiovascular disease.

A single-gene cause in 29.5% of cases of steroid-resistant nephrotic syndrome

Steroid-resistant nephrotic syndrome (SRNS) is the second most frequent cause of ESRD in the first two decades of life. Effective treatment is lacking. First insights into disease mechanisms came from identification of single-gene causes of SRNS. However, the frequency of single-gene causation and its age distribution in large cohorts are unknown. We performed exon sequencing of NPHS2 and WT1 for 1783 unrelated, international families with SRNS. We then examined all patients by microfluidic multiplex PCR and next-generation sequencing for all 27 genes known to cause SRNS if mutated. We detected a single-gene cause in 29.5% (526 of 1783) of families with SRNS that manifested before 25 years of age. The fraction of families in whom a single-gene cause was identified inversely correlated with age of onset. Within clinically relevant age groups, the fraction of families with detection of the single-gene cause was as follows: onset in the first 3 months of life (69.4%), between 4 and 12 months old (49.7%), between 1 and 6 years old (25.3%), between 7 and 12 years old (17.8%), and between 13 and 18 years old (10.8%). For PLCE1, specific mutations correlated with age of onset. Notably, 1% of individuals carried mutations in genes that function within the coenzyme Q10 biosynthesis pathway, suggesting that SRNS may be treatable in these individuals. Our study results should facilitate molecular genetic diagnostics of SRNS, etiologic classification for therapeutic studies, generation of genotype-phenotype correlations, and the identification of individuals in whom a targeted treatment for SRNS may be available.

Dimethylarginines as risk markers of atherosclerosis and chronic kidney disease in children with nephrotic syndrome

BACKGROUND

Nephrotic syndrome in children is commonly associated with dyslipidemia, which is considered a risk factor for endothelial dysfunction and atherosclerosis. Recently new markers of endothelial dysfunction, such as asymmetric dimethylarginine (ADMA), have gained importance. Another L-arginine derivative--symmetric dimethylarginine (SDMA)--may reflect the glomerular filtration rate (GFR).

OBJECTIVES

The main aim of this study was to assess ADMA as a marker of atherosclerosis. Secondly, SDMA was examined for GFR assessment.

MATERIAL AND METHODS

The study involved 32 children with nephrotic syndrome. Several parameters were examined in the remission and relapse phases of nephrotic syndrome, including ADMA, SDMA, cholesterol, triglycerides and GFR.

RESULTS

In the relapse phase there was a negative correlation between ADMA and lipids (cholesterol and triglycerides). In both phases SDMA was negatively correlated with GFR.

CONCLUSIONS

The role of ADMA as a marker for endothelial dysfunction is not significant. SDMA may be utilized to monitor GFR in children with nephrotic syndrome.

Enhanced Steroid Therapy in Adult Minimal Change Nephrotic Syndrome: A Systematic Review and Meta-analysis

The best regimen for adult minimal change nephrotic syndrome (MCNS) is still unknown. Due to an excessive number of adverse events caused by oral steroid monotherapy, enhanced steroid therapy (low dose of prednisolone with a short course of methylprednisolone or with another immunosuppressant) has been studied extensively for years. In this study, the PubMed, Embase, EBSCO and Cochrane Library databases were searched for clinical trials which compared enhanced steroid therapy with oral steroid monotherapy in adult MCNS and a meta-analysis was performed. Seven studies involving 357 patients were included. We found that patients treated with enhanced steroid therapy responded more quickly to complete remission (CR) [mean difference = -9.52, 95% confidence interval (CI): -12.66--6.39, p<0.00001] and showed fewer adverse events [risk radio (RR) = 0.72, 95% CI: 0.54-0.97, p=0.03] than patients receiving oral steroid monotherapy. The CR rate (RR= 0.96, 95% CI: 0.83-1.10, p=0.53) and relapse rate (RR=0.87, 95% CI: 0.57-1.34, p=0.53) were similar in both groups.