Comprehensive evaluation of patients with primary hyperoxaluria type 1: A nationwide study.

BACKGROUND: Primary hyperoxaluria type 1 (PH1) is characterized by increased endogenous oxalate production and deposition as calcium oxalate crystals. The main manifestations are nephrocalcinosis/nephrolithiasis, causing impaired kidney function. We aimed to evaluate the clinical characteristics and overall outcomes of paediatric PH1 patients in Turkey. METHODS: This is a nationwide, multicentre, retrospective study evaluating all available paediatric PH1 patients from 15 different paediatric nephrology centres in Turkey. Detailed patient data was collected which included demographic, clinical and laboratory features. Patients were classified according to their age and characteristics at presentation: patients presenting in the first year of life with nephrocalcinosis/nephrolithiasis (infantile oxalosis, Group 1), cases with recurrent nephrolithiasis diagnosed during childhood (childhood-onset PH1, Group 2), and asymptomatic children diagnosed with family screening (Group 3). RESULTS: Forty-eight patients had a mutation consistent with PH1. The most common mutation was c.971_972delTG (25%). Infantile oxalosis patients had more advanced chronic kidney disease (CKD) or kidney failure necessitating dialysis (76.9% vs. 45.5%). These patients had much worse clinical course and mortality rates seemed to be higher (23.1% vs. 13.6%). Patients with fatal outcomes were the ones with significant comorbidities, especially with cardiovascular involvement. Patients in Group 3 were followed with better outcomes, with no kidney failure or mortality. CONCLUSION: PH1 is not an isolated kidney disease but a systemic disease. Family screening helps to preserve kidney function and prevent systemic complications. Despite all efforts made with traditional treatment methods including transplantation, our results show devastating outcomes or mortality.

High C-reactive protein and number of previous episodes at diagnosis increase the risk of catheter removal in peritoneal dialysis-related peritonitis in children.

BACKGROUND: A minority of patients with peritonitis require removal of peritoneal dialysis (PD) catheters. We examined risk factors at diagnosis that could predict the removal of PD catheter before obtaining the results of treatment success in children with peritonitis. METHODS: We analyzed 156 peritonitis episodes in 57 pediatric PD patients. RESULTS: The peritonitis rate was 0.68 peritonitis episode per patient year. Catheter removal was required in 22 of 156. C-reactive protein (CRP) ≥ ×10 of upper limit at diagnosis and increased previous episode number were found to be associated with catheter removal (OR [95% CI] 6.4 [2.3-18.1], p = 0.001 and 3.8 [1.4-10.6], p = 0.009). CONCLUSION: These findings supported that CRP could be an early marker in predicting catheter removal even before obtaining the results of treatment success. Furthermore, it should be kept in mind that the risk of catheter removal is high in patients with high number of previous episodes especially of three or more.

Automated complete blood counter, urine analyzer and urine dipstick test results are correlated with thoma cell counting chamber counts in the diagnosis of dialysis related peritonitis in children.

INTRODUCTION: Peritoneal dialysis is the treatment of choice for end-stage renal disease. Peritoneal dialysis related peritonitis is of great importance for patient and technical survival. The aim of our study was to evaluate the accuracy and the correlation between the three methods (complete blood count, urinalysis device, urine dipstick test) and with the reference manual method (Thoma Cell Counter Chamber). MATERIALS AND METHODS: We retrospectively analyzed 167 peritoneal fluid samples taken from 25 patients receiving peritoneal dialysis treatment. Leukocyte counts were evaluated with Thoma Cell Counter Chamber, complete blood count, urinalysis device and urine dipstick test. RESULTS: There was a significant positive correlation between Thoma Cell Counter Chamber and complete blood count results (Spearman's rho=0.70), between Thoma Cell Counter Chamber and urinalysis device (Spearman's rho=0.73), and between Thoma Cell Counter Chamber and urine dipstick test (Spearman's rho=0.71). Area under curve for complete blood count, urinalysis device and urine dipstick test were 0.93, 0.94 and 0.89 respectively, indicating good accuracy. Sensitivity and specificity were 89.7% and 86.7% in the complete blood count analysis (associated criterion: 130 cells/mm3). Sensitivity and specificity were 89.7% and 86.7% in the urinalysis device (associated criterion: 10 cells/HPF). Sensitivity and specificity were 79.6% and 91.4% when in the urine dipstick test analysis (associated criterion: +1 positivity). The Bland-Altman plot showed good agreement. CONCLUSION: Automatic complete blood count and urinalysis devices have good correlation and agreement with manual method in the diagnosis of peritonitis in the pediatric age group. Urine dipstick test in the home setting can be useful for screening patients with suspected peritonitis.

Parathyroid hormone and phosphate homeostasis in patients with Bartter and Gitelman syndrome: an international cross-sectional study.

BACKGROUND: Small cohort studies have reported high parathyroid hormone (PTH) levels in patients with Bartter syndrome and lower serum phosphate levels have anecdotally been reported in patients with Gitelman syndrome. In this cross-sectional study, we assessed PTH and phosphate homeostasis in a large cohort of patients with salt-losing tubulopathies. METHODS: Clinical and laboratory data of 589 patients with Bartter and Gitelman syndrome were provided by members of the European Rare Kidney Diseases Reference Network (ERKNet) and the European Society for Paediatric Nephrology (ESPN). RESULTS: A total of 285 patients with Bartter syndrome and 304 patients with Gitelman syndrome were included for analysis. Patients with Bartter syndrome type I and II had the highest median PTH level (7.5 pmol/L) and 56% had hyperparathyroidism (PTH >7.0 pmol/L). Serum calcium was slightly lower in Bartter syndrome type I and II patients with hyperparathyroidism (2.42 versus 2.49 mmol/L; P = .038) compared to those with normal PTH levels and correlated inversely with PTH (rs -0.253; P = .009). Serum phosphate and urinary phosphate excretion did not correlate with PTH. Overall, 22% of patients had low serum phosphate levels (phosphate-standard deviation score < -2), with the highest prevalence in patients with Bartter syndrome type III (32%). Serum phosphate correlated with tubular maximum reabsorption of phosphate/glomerular filtration rate (TmP/GFR) (rs 0.699; P < .001), suggesting renal phosphate wasting. CONCLUSIONS: Hyperparathyroidism is frequent in patients with Bartter syndrome type I and II. Low serum phosphate is observed in a significant number of patients with Bartter and Gitelman syndrome and appears associated with renal phosphate wasting.

Aetiology, course and treatment of acute tubulointerstitial nephritis in paediatric patients: a cross-sectional web-based survey.

BACKGROUND: Acute tubulointerstitial nephritis (TIN) is a significant cause of acute renal failure in paediatric and adult patients. There are no large paediatric series focusing on the aetiology, treatment and courses of acute TIN. PATIENTS, DESIGN AND SETTING: We collected retrospective clinical data from paediatric patients with acute biopsy-proven TIN by means of an online survey. Members of four professional societies were invited to participate. RESULTS: Thirty-nine physicians from 18 countries responded. 171 patients with acute TIN were included (54% female, median age 12 years). The most frequent causes were tubulointerstitial nephritis and uveitis syndrome in 31% and drug-induced TIN in 30% (the majority of these caused by non-steroidal anti-inflammatory drugs). In 28% of patients, no initiating noxae were identified (idiopathic TIN). Median estimated glomerular filtration rate (eGFR) rose significantly from 31 at time of renal biopsy to 86 mL/min/1.73 m2 3-6 months later (p<0.001). After 3-6 months, eGFR normalised in 41% of patients (eGFR ≥90 mL/min/1.73 m2), with only 3% having severe or end-stage impairment of renal function (<30 mL/min/1.73 m2). 80% of patients received corticosteroid therapy. Median eGFR after 3-6 months did not differ between steroid-treated and steroid-untreated patients. Other immunosuppressants were used in 18% (n=31) of patients, 21 of whom received mycophenolate mofetil. CONCLUSIONS: Despite different aetiologies, acute paediatric TIN had a favourable outcome overall with 88% of patients showing no or mild impairment of eGFR after 3-6 months. Prospective randomised controlled trials are needed to evaluate the efficacy of glucocorticoid treatment in paediatric patients with acute TIN.

The assesment of prothrombotic potential using thrombin generation assay in pediatric patients with nephrotic syndrome: preliminary study.

BACKGROUND: Nephrotic syndrome (NS) is a common kidney disease associated with an increased risk of thrombotic events. The aim of this study was to assess the prothrombotic potential of patients with NS using the thrombin generation assay (TGA). METHODS: A total of 35 patients with NS, who were followed in the Division of Pediatric Nephrology in Behcet Uz Children`s Hospital, were included in the study. After the patients with Steroid Resistant NS (n:3) were excluded, 32 patients in total were evaluated for TGA. Patients were primarily classified according to their response to corticosteroid therapy. The control group consisted of 34 healthy volunteers with similar gender and age distribution to the patients. Blood urine nitrogen, creatinine, albumin, triglyceride, cholesterol, 24-hour proteinuria, platelets, erythrocyte sedimentation rate, C-reactive protein and thrombin generation values in activation and remission period of NS were compared. Moreover, TGA values of the patients in their remission period were compared with the values of those in the control group. RESULTS: Endogenous thrombin potential (ETP) and peak thrombin levels were significantly higher in the activation period than remission period of NS. Additionally, after the patients achieved remission, their ETP was still higher than the control group. There was a negative correlation between both ETP and peak thrombin levels of patients with serum albumin, whereas a significant positive correlation was detected with platelet levels. Thromboembolic events were not observed in any of the patients during follow-up. CONCLUSIONS: Nephrotic syndrome is strongly associated with hypercoagulopathy as assessed by TGA during active NS. The present study reinforces the usefulness of TGA as a marker of hypercoagulability in pediatric patients with NS. Further studies are needed in this regard.

Children with chronic-refractory autoimmune cytopenias: a single center experience.

BACKGROUND AND OBJECTIVES: Autoimmune cytopenias are a group of heterogeneous disorders characterized by immune-mediated destruction of one or more hematopoietic lineage cells. The differential diagnosis of children with autoimmune cytopenias requires much time and laboratory investigations. The aim of the present study was to evaluate the clinical course and significance of autoimmune cytopenias due to immunodeficiency or autoimmune diseases in children at a single children`s hospital. METHOD: Between February 1997 and September 2015, chronic/refractory autoimmune cytopenias patient data were evaluated retrospectively. Twenty-three patients were assessed in this study. RESULTS: The median duration of following was 2.6 years (4 months-18.5 years). The median age of diagnosis was 3.1 years (6 months-16 years). A total of 13 patients (56.5%) had single-lineage and 10 (46.5%) had multilineage cytopenias. The most frequent single-lineage cytopenia was thrombocytopenia, followed by anemia. In 22 of the patients, cytopenias was detected before the primary diseases. All of the patients were treated with corticosteroids or intravenous immune globulin as first-line treatment. Ten patients (43.5%) needed second or further-line immunosuppressive therapies that patients diagnosed as systemic lupus erythematosus, hypogammaglobulinemia, or common variable immunodeficiency. A total of 8 patients (34.7%) recovered from autoimmune cytopenias after the treatment of primer disease. Cytopenias were continued in 14 patients. CONCLUSION: Cytopenia may be the first finding of an immunodeficiency or autoimmune disease and primary disease may be diagnosed in the clinical course. Taking the new targeted treatment options into consideration; early diagnosis is likely to become more important in the near-future in order to begin the treatment for the underlying disease as early as possible.

Una nueva mutación asociada con el síndrome de Pierson / A new mutation associated with Pierson syndrome

El síndrome de Pierson se caracteriza por la presencia de síndrome nefrótico congénito y microcoria bilateral. Genéticamente, este trastorno está ocasionado por mutaciones en el gen LAMB2, que codifica la cadenaß2 de la laminina. Hasta la fecha, en la bibliografía se informaron 98casos y 50mutaciones diferentes. No existen terapias específicas para el síndrome de Pierson, y el tratamiento es complementario. El pronóstico es malo por la disfunción renal progresiva y las complicaciones de la insuficiencia renal. En este artículo, se informa sobre una mutación homocigota novedosa (c.1890G>C [p.Q630H]) en el gen LAMB2 en una paciente con síndrome de Pierson que tenía un fenotipo atípico, como epidermólisis ampollosa.

Pierson syndrome is characterized by congenital nephrotic syndrome and bilateral microcoria. Genetically, mutations in the LAMB2 gene, which encodes the laminin ß2 chain, lead to this disorder. To date, 98 cases and 50 different mutations have been reported in literature. There are no specific therapies for Pierson syndrome and treatment is supportive. The prognosis is poor because of progressive impairment of renal function and complications of renal failure. We report a novel homozygous mutation (c.1890G>T, p.Q630H) in the LAMB2 gene in a patient with Pierson syndrome who had atypical phenotypic feature such as epidermolysis bullosa

A new mutation associated with Pierson syndrome. / Una nueva mutación asociada con el síndrome de Pierson.

Pierson syndrome is characterized by congenital nephrotic syndrome and bilateral microcoria. Genetically, mutations in the LAMB2 gene, which encodes the laminin ß2 chain, lead to this disorder. To date, 98 cases and 50 different mutations have been reported in literature. There are no specific therapies for Pierson syndrome and treatment is supportive. The prognosis is poor because of progressive impairment of renal function and complications of renal failure. We report a novel homozygous mutation (c.1890G>T, p.Q630H) in the LAMB2 gene in a patient with Pierson syndrome who had atypical phenotypic feature such as epidermolysis bullosa.

El síndrome de Pierson se caracteriza por la presencia de síndrome nefrótico congénito y microcoria bilateral. Genéticamente, este trastorno está ocasionado por mutaciones en el gen LAMB2, que codifica la cadena ß2 de la laminina. Hasta la fecha, en la bibliografía se informaron 98 casos y 50 mutaciones diferentes. No existen terapias específicas para el síndrome de Pierson, y el tratamiento es complementario. El pronóstico es malo por la disfunción renal progresiva y las complicaciones de la insuficiencia renal. En este artículo, se informa sobre una mutación homocigota novedosa (c.1890G>C [p.Q630H]) en el gen LAMB2 en una paciente con síndrome de Pierson que tenía un fenotipo atípico, como epidermólisis ampollosa.

Challenges in the management of an ignored cause of hyperammonemic encephalopathy: pyruvate carboxylase deficiency.

Pyruvate carboxylase (PC) deficiency is a rare autosomal recessive disease and provides clinics in three essential phenotypes. Type B PC deficiency is characterized by lactic acidosis and hyperammonemia. We report a Turkish patient who was diagnosed with type B PC deficiency. Despite the application of anaplerotic treatment with biotin, citrate and arginine-aspartate, continuous veno-venous hemodialysis (CVVHD) treatments were applied due to the failure to keep hyperammonemia and lactic acidosis under control. Ammonia values increasing to 860 µmol/L were observed. A homozygous novel variant was detected in PC gene analyses containing a 12-base pair deletion on exon 8. Although the mutation found was not reported previously, it was accepted as a pathogenic variant due to its presence in a functional region of the protein. In type B PC deficiency, although a high level of ammonia is expected, it rarely exceeds 200 µmol/L. As far as we know, the present case has the highest ammonia values in the literature. This paper has been shared to highlight to keep PC deficiency in mind regarding the differential diagnosis of hyperammonemia, particularly in the presence of lactic acidosis, and to serve as a model for the use of different modalities in the management process of PC deficiency.

Colostomy in children on chronic peritoneal dialysis.

BACKGROUND: This study aimed to evaluate outcome of children on chronic peritoneal dialysis (PD) with a concurrent colostomy. METHODS: Patients were identified through the International Pediatric Peritoneal Dialysis Network (IPPN) registry. Matched controls were randomly selected from the registry. Data were collected through the IPPN database and a survey disseminated to all participating sites. RESULTS: Fifteen centers reported 20 children who received chronic PD with a co-existing colostomy. The most common cause of end stage kidney disease was congenital anomalies of the kidney and urinary tract (n = 16, 80%). The main reason for colostomy placement was anorectal malformation (n = 13, 65%). The median age at colostomy creation and PD catheter (PDC) insertion were 0.1 (IQR, 0-2.2) and 2.8 (IQR 0.2-18.8) months, respectively. The colostomies and PDCs were present together for a median 18 (IQR, 4.9-35.8) months. The median age at PDC placement in 46 controls was 3.4 (IQR, 0.2-7.4) months of age. Fourteen patients (70%) developed 39 episodes of peritonitis. The annualized peritonitis rate was significantly higher in the colostomy group (1.13 vs. 0.70 episodes per patient year; p = 0.02). Predominant causative microorganisms were Staphylococcus aureus (15%) and Pseudomonas aeruginosa (13%). There were 12 exit site infection (ESI) episodes reported exclusively in colostomy patients. Seven colostomy children (35%) died during their course of PD, in two cases due to peritonitis. CONCLUSION: Although feasible in children with a colostomy, chronic PD is associated with an increased risk of peritonitis and mortality. Continued efforts to reduce infection risk for this complex patient population are essential.

Global Variation of Nutritional Status in Children Undergoing Chronic Peritoneal Dialysis: A Longitudinal Study of the International Pediatric Peritoneal Dialysis Network.

While children approaching end-stage kidney disease (ESKD) are considered at risk of uremic anorexia and underweight they are also exposed to the global obesity epidemic. We sought to investigate the variation of nutritional status in children undergoing chronic peritoneal dialysis (CPD) around the globe. The distribution and course of body mass index (BMI) standard deviation score over time was examined prospectively in 1001 children and adolescents from 35 countries starting CPD who were followed in the International Pediatric PD Network (IPPN) Registry. The overall prevalence of underweight, and overweight/obesity at start of CPD was 8.9% and 19.7%, respectively. Underweight was most prevalent in South and Southeast Asia (20%), Central Europe (16.7%) and Turkey (15.2%), whereas overweight and obesity were most common in the Middle East (40%) and the US (33%). BMI SDS at PD initiation was associated positively with current eGFR and gastrostomy feeding prior to PD start. Over the course of PD BMI SDS tended to increase on CPD in underweight and normal weight children, whereas it decreased in initially overweight patients. In infancy, mortality risk was amplified by obesity, whereas in older children mortality was markedly increased in association with underweight. Both underweight and overweight are prevalent in pediatric ESKD, with the prevalence varying across the globe. Late dialysis start is associated with underweight, while enteral feeding can lead to obesity. Nutritional abnormalities tend to attenuate with time on dialysis. Mortality risk appears increased with obesity in infants and with underweight in older children.

The role of cardiac troponin T in detection of cardiac damage and long term mortality in children with chronic renal disease.

Karadas U, Özdemir Karadas N, Bak M, Serdaroglu E, Yilmazer MM, Mese T. The role of cardiac troponin T in detection of cardiac damage and long term mortality in children with chronic renal disease. Turk J Pediatr 2019; 61: 873-878. In this study, we aimed to evaluate the role of cardiac troponin T (cTnT) in detecting myocardial involvement in children with chronic kidney disease (CKD) and to investigate whether it contributes to predicting cardiac involvement and mortality at follow-up. Echocardiographic evaluations were performed on a sample of 69 patients, of which 33 (47.8%) were female, with grade 3, 4 and 5 chronic renal failure and end-stage renal failure. Patients with normal cTnT levels and patients with high cTnT levels were compared. cTnT levels were observed to be high in 13 (19%) of the 69 patients. The comparison between the patients with normal cTnT levels and patients with high cTnT levels with regards to the echocardiographic findings revealed that in the latter group, the average ejection fraction and fractional shortening levels were lower (p=0.003 and p=0.013, respectively), the detection rate of left ventricular systolic dysfunction was 5.5 times higher and the rate of detection of left ventricular hypertrophy (LVH) was 3 times higher (p=0.004, p=0.011). In this study, it was shown that it is possible to obtain information about cardiac effects by examining the serum cTnT level before clinical symptoms occur in children with CKD, and that cTnT can be used for screening purposes.

The Emerging Resistance in Nosocomial Urinary Tract Infections: From the Pediatrics Perspective.

BACKGROUND: Healthcare-associated infections results in increased health care costs and mortality. There are limited studies concerning the distribution of the etiologic agents and the resistance patterns of the microorganisms causing healthcare-associated urinary tract infections (HA-UTI) in pediatric settings. OBJECTIVES: The aim of this study was to evaluate the distribution and antibiotic susceptibility patterns of pathogens causing HA-UTI in children. MATERIAL AND METHODS: Isolates from 138 children with UTI who were hospitalized in pediatric, neonatal and pediatric surgery intensive care units were reviewed. RESULTS: Most common isolated organism was Klebsiella pneumoniae (34.1%) and Escherichia coli (26.8%). Among the Pseudomonas aeruginosa, Meropenem and imipenem resistance rates were 46.2% and 38.5%. Extended-spectrum beta-lactamase (ESBL) production was present in 48 Klebsiella species (82.8%). Among ESBL positive Klebsiella species, the rate of meropenem and imipenem resistance was 18.8%, and ertapenem resistance was 45.9%. Extended spectrum beta-lactamase production was present in 27 (72.9%) Escherichia coli species. Among ESBL positive E. coli, the rate of meropenem and imipenem resistance was 7.4%, and ertapenem resistance was 14.8. CONCLUSIONS: Emerging meropenem resistance in P. aeruginosa, higher rates of ertapenem resistance in ESBL positive ones in E. coli and Klebsiella species in pediatric nosocomial UTI are important notifying signs for superbug infections.

Mutations in multiple components of the nuclear pore complex cause nephrotic syndrome.

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

Time-averaged hemoglobin values, not hemoglobin cycling, have an impact on outcomes in pediatric dialysis patients.

BACKGROUND: During erythropoietin-stimulating agent (ESA) treatment, hemoglobin (Hb) levels usually fluctuate; this phenomenon is known as "Hb cycling (HC)." In this study, we aimed to evaluate the predictors of HC and its impact on left ventricular hypertrophy (LVH) as a patient-important outcome parameter in pediatric dialysis patients. METHODS: Records of patients followed up in nine pediatric nephrology centers between 2008 and 2013 were reviewed. More than 1 g/dL decrease or increase in Hb level was considered as HC. Patients were divided into two groups according to 12-month Hb trajectory as rare cycling (RC) (≤ 3) and frequent cycling (FC) (> 3 fluctuation) as well as three groups based on T-A-Hb levels: < 10, 10-11, and > 11 g/dL. RESULTS: Two hundred forty-five dialysis (160 peritoneal dialysis (PD) and 85 hemodialysis (HD)) patients aged 12.3 ± 5.1 (range 0.5-21) years were enrolled in this study. Fifty-two percent of the patients had RC, 45% had FC, and only 3% had no cycling. There were no differences between HC groups with respect to age, dialysis modality, having anemia, hospitalization rate, residual urine volume, and mortality. Although left ventricular mass index (LVMI) tended to be higher in RC than FC group (65 ± 37 vs 52 ± 23 g/m2.7, p = 0.056), prevalence of LVH was not different between the groups (p = 0.920). In regression analysis, FC was not a risk factor for LVH, but low T-A Hb level (< 10 g/dL) was a significant risk for LVH (OR = 0.414, 95% CI 0.177-0.966, p = 0.04). The target Hb levels were more often achieved in PD patients, and the number of deaths was significantly lower in non-anemic patients (Hb level > 11 g/dL). CONCLUSION: Hb cycling is common among dialysis patients. Severity of anemia rather than its cycling has more significant impact on the prevalence of LVH and on inflammatory state.

The Clinical and Mutational Spectrum of Turkish Patients with Cystinosis.

BACKGROUND AND OBJECTIVES: Infantile nephropathic cystinosis is a severe disease that occurs due to mutations in the cystinosis gene, and it is characterized by progressive dysfunction of multiple organs; >100 cystinosis gene mutations have been identified in multiple populations. Our study aimed to identify the clinical characteristics and spectrum of cystinosis gene mutations in Turkish pediatric patients with cystinosis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We identified the clinical characteristics and spectrum of cystinosis gene mutations in Turkish patients with cystinosis in a multicenter registry that was established for data collection. The data were extracted from this registry and analyzed. RESULTS: In total, 136 patients (75 men and 61 women) were enrolled in the study. The most common clinical findings were growth retardation, polyuria, and loss of appetite. None of the patients had the 57-kb deletion, but seven novel mutations were identified. The most common mutations identified were c.681G>A (p.Glu227Glu; 31%), c.1015G>A (p.Gly339Arg; 22%), and c.18_21 del (p.Thr7Phefs*7; 14%). These mutations were associated with earlier age of disease onset than the other mutations. To understand the effects of these allelic variants on clinical progression, the mutations were categorized into two major groups (missense versus deletion/duplication/splice site). Although patients with missense mutations had a better eGFR at the last follow-up visit, the difference was not significant. Patients in whom treatment began at age <2 years old had later onset of ESRD (P=0.02). Time to ESRD did not differ between the patients with group 1 and group 2 mutations. CONCLUSIONS: The most common cystinosis gene mutations identified in Turkey were c.681G>A (p.Glu227Glu), c.1015G>A (p.Gly339Arg), and c.18_21 del (p.Thr7Phefs*7). Patients with less severe cystinosis gene mutations tend to have better kidney outcome.

Effect of the timing of dialysis initiation on left ventricular hypertrophy and inflammation in pediatric patients.

BACKGROUND: The optimal time for dialysis initiation in adults and children with chronic kidney disease remains unclear. The aim of this study was to evaluate the impact of dialysis timing on different outcome parameters, in particular left ventricular (LV) morphology and inflammation, in pediatric patients receiving peritoneal dialysis and hemodialysis. METHODS: The medical records of pediatric dialysis patients who were followed-up in nine pediatric nephrology centers in Turkey between 2008 and 2013 were retrospectively reviewed. In addition to demographic data, we retrieved anthropometric measurements, data on dialysis treatment modalities, routine biochemical parameters, complete blood count, serum ferritin, parathormone, C-reactive protein (CRP), and albumin levels, as well as echocardiographic data and hospitalization records. The patients were divided into two groups based on their estimated glomerular filtration rate (eGFR) levels at dialysis initiation, namely, an early-start group, characterized by an eGFR of >10 ml/min/1.73 m2, and a late-start group, with an eGFR of < 7 ml/min/1.73 m2. The collected data were compared between these groups. RESULTS: A total of 245 pediatric dialysis patients (mean age ± standard deviation 12.3 ± 5.1 years, range 0.5-21 years) were enrolled in this study. Echocardiographic data were available for 137 patients, and the mean LV mass index (LVMI) was 58 ± 31 (range 21-215) g/m2.7. The LVMI was 75 ± 30 g/m2.7(n = 81) and 34 ± 6 g/m2.7(n = 56) in patients with or without LV hypertrophy (LVH) (p < 0.001). Early-start (eGFR >10 ml/min/1.73 m2) versus late-start dialysis (eGFR < 7 ml/min/1.73 m2) groups did not significantly differ in LVMI and LVH status (p > 0.05) nor in number of hospitalizations. Serum albumin levels were significantly higher in the early-dialysis group compared with the late-dialysis group (3.3 ± 0.7 vs. 3.1 ± 0.7 g/dl, respectively; p < 0.05). The early-start group had relatively higher time-averaged albumin levels (3.2 ± 0.5 vs. 3.1 ± 0.5 g/dl; p = > 0.05) and relatively lower CRP levels (3.64 ± 2.00 vs. 4.37 ± 3.28 mg/L, p > 0.05) than the late-start group, but these differences did not reach statistical significance. CONCLUSION: Although early dialysis initiation did not have a significant effect on important clinical outcome parameters, including LVH, inflammatory state, and hospitalization, in our pediatric dialysis patients, this area of study deserves further attention.

Peritoneal Dialysis Access Revision in Children: Causes, Interventions, and Outcomes.

BACKGROUND AND OBJECTIVES: Little published information is available about access failure in children undergoing chronic peritoneal dialysis. Our objectives were to evaluate frequency, risk factors, interventions, and outcome of peritoneal dialysis access revision. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Data were derived from 824 incident and 1629 prevalent patients from 105 pediatric nephrology centers enrolled in the International Pediatric Peritoneal Dialysis Network Registry between 2007 and 2015. RESULTS: In total, 452 access revisions were recorded in 321 (13%) of 2453 patients over 3134 patient-years of follow-up, resulting in an overall access revision rate of 0.14 per treatment year. Among 824 incident patients, 186 (22.6%) underwent 188 access revisions over 1066 patient-years, yielding an access revision rate of 0.17 per treatment year; 83% of access revisions in incident patients were reported within the first year of peritoneal dialysis treatment. Catheter survival rates in incident patients were 84%, 80%, 77%, and 73% at 12, 24, 36, and 48 months, respectively. By multivariate logistic regression analysis, risk of access revision was associated with younger age (odds ratio, 0.93; 95% confidence interval, 0.92 to 0.95; P<0.001), diagnosis of congenital anomalies of the kidney and urinary tract (odds ratio, 1.28; 95% confidence interval, 1.03 to 1.59; P=0.02), coexisting ostomies (odds ratio, 1.42; 95% confidence interval, 1.07 to 1.87; P=0.01), presence of swan neck tunnel with curled intraperitoneal portion (odds ratio, 1.30; 95% confidence interval, 1.04 to 1.63; P=0.02), and high gross national income (odds ratio, 1.10; 95% confidence interval, 1.02 to 1.19; P=0.01). Main reasons for access revisions included mechanical malfunction (60%), peritonitis (16%), exit site infection (12%), and leakage (6%). Need for access revision increased the risk of peritoneal dialysis technique failure or death (hazard ratio, 1.35; 95% confidence interval, 1.10 to 1.65; P=0.003). Access dysfunction due to mechanical causes doubled the risk of technique failure compared with infectious causes (hazard ratio, 1.95; 95% confidence interval, 1.20 to 2.30; P=0.03). CONCLUSIONS: Peritoneal dialysis catheter revisions are common in pediatric patients on peritoneal dialysis and complicate provision of chronic peritoneal dialysis. Attention to potentially modifiable risk factors by pediatric nephrologists and pediatric surgeons should be encouraged.