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Purpose: To analyze electrocardiograms (ECGs) of patients with a salt-losing tubulopathy (SLT) and to determine the frequency and risk factors for long QT and arrhythmia. Methods: A total of 203 patients aged <19 years with SLT, specifically Bartter syndrome and Gitelman syndrome, who had a 12-lead ECG were included in this retrospective study. We analyzed the presence of an arrhythmia or prolonged corrected QT (QTc) on ECGs obtained for these patients. Demographic and laboratory data were compared between patients with abnormal and normal ECG findings. Results: Out of the 203 SLT patients, 38 (18.7%) underwent electrocardiography and 10 (40.0%) of 25 patients with inherited SLT had abnormal ECG findings, including prolonged QTc and arrhythmias. The abnormal ECG group had significantly lower serum potassium levels than the normal group (median [interquartile range]: 2.50 mmol/L [2.20-2.83] vs. 2.90 mmol/L [2.70-3.30], P=0.036), whereas other serum chemistry values did not show significant differences. The cutoff level for a significant difference in QTc interval was serum potassium level <2.50 mmol/L. One cardiac event occurred in a 13-year-old boy, who developed paroxysmal supraventricular tachycardia and underwent cardiac ablation. No sudden cardiac deaths occurred in this cohort. Conclusions: The incidence of ECG abnormalities in patients with inherited SLT was 40.0%, whereas the ECG screening rate was relatively low (18.7%). Therefore, we recommend ECG screening in patients with inherited SLT, especially in those with serum potassium level <2.50 mmol/L. [ABSTRACT FROM AUTHOR]

While the incidence of nephrotic syndrome (NS) is decreasing in Korea, the morbidity of difficult-totreat NS is significant. Efforts to minimize treatment toxicity showed that prolonged treatment after an initial treatment for 2-3 months with glucocorticosteroids was not effective in reducing frequent relapses. For steroid-dependent NS, rituximab, a monoclonal antibody against the CD20 antigen on B cells, was proven to be as effective, and short-term daily low-dose steroids during upper respiratory infections reduced relapses. Steroid resistance or congenital NS are indications for genetic study and renal biopsy, since the list of genes involved in NS is lengthening. [ABSTRACT FROM AUTHOR]

Purpose: The use of a 12-week steroid regimen (long-term therapy, LT) for the first episode of idiopathic nephrotic syndrome (NS) reportedly induces a more sustained remission and lower relapse rate than previous regimens, including an 8-week steroid regimen (short-term therapy, ST). Here, we assessed the potential for selective application of 2 steroid regimens (LT vs. ST) based on the days to remission (early responders [ER] vs. late responders [LR]) for the first idiopathic NS episode in children. Methods: Patients were divided into 4 subgroups (ST+ER, ST+LR, LT+ER, and LT+LR) according to the initial steroid regimen used and rapidity of response; the baseline characteristics, relapse rates, and cumulative percentage of children with sustained remission were then compared among the 4 subgroups. Results: Fifty-four children received ST, and the remaining 45 children received LT. As observed in previous studies, children receiving LT showed significantly lower relapse rates during the first year after the first NS episode than those receiving ST. The ST+ER group showed significantly lower relapse rates during the first one year and two years after the first NS episode than the the ST+LR group, whereas there were no significant differences of the relapse rates and duration to the first relapse between the ST+ER and LT+ER groups. Conclusion: We suggest that the initial steroid regimen in idiopathic NS patients can be shortened according to the duration to remission i.e., LT in patients achieving remission after the first week of steroid therapy, and ST in those achieving remission within the first week of steroid therapy. [ABSTRACT FROM AUTHOR]

Adult Korean patients on chronic dialysis have a 9-year survival rate of 50%, with cardiovascular problems being the most significant cause of death. The 2011 annual report of the North American Pediatric Renal Trials and Collaborative Studies group reported 3-year survival rates of 93.4% and relatively poorer survival in younger patients. In this study, we have reviewed data from Korean pediatric chronic kidney disease registry from 2002 to 2010 to assess survival rates and causes of death in Korean children on chronic dialysis. The overall estimated patient survival rates were 98.4%, 94.4%, and 92.1% at 1, 3, and 5 years, respectively. No significant difference was observed in survival rates between patients on peritoneal dialysis and those on hemodialysis. Patients for whom dialysis was initiated before 2 years of age (n=40) had significantly lower survival rates than those for whom dialysis was initiated at 6-11 years of age (n=140). In all, 26 patients had died; the mortality rate was 19.9 per 1,000 patient years. The most common causes of death were infections and comorbidities such as malignancy and central nervous system (CNS) or liver diseases. The outcomes observed in this study were better than those observed in adults and comparable to those observed in pediatric studies in other countries. To improve the outcomes of children on chronic dialysis, it is necessary to prevent dialysis-related complications such as infection, congestive heart failure, or CNS hemorrhage and best control treatable comorbidities. [ABSTRACT FROM AUTHOR]

Hemolytic uremic syndrome (HUS) is one of the most common causes of acute renal failure in childhood and is primarily diagnosed in up to 4.5% of children who undergo chronic renal replacement therapy. Escherichia coli serotype O157:H7 is the predominant bacterial strain identified in patients with HUS; more than 100 types of Shiga toxin-producing enterohemorrhagic E. coli (EHEC) subtypes have also been isolated. The typical HUS manifestations are microangiopathic hemolytic anemia, thrombocytopenia, and renal insufficiency. In typical HUS cases, more serious EHEC manifestations include severe hemorrhagic colitis, bowel necrosis and perforation, rectal prolapse, peritonitis, and intussusceptions. Colonic perforation, which has an incidence of 1-2%, can be a fatal complication. In this study, we report a typical Shiga toxin-associated HUS case complicated by small intestinal perforation with refractory peritonitis that was possibly because of ischemic enteritis. Although the degree of renal damage is the main concern in HUS, extrarenal complications should also be considered in severe cases, as presented in our case. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to compare the outcome of carbapenem versus non-carbapenem antimicrobial therapy for pediatric urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL) producing Enterobacteriaceae. Materials and Methods: From 2006 to 2011, 42 episodes of UTI caused by ESBL-producing Enterobacteriaceae were diagnosed at Seoul National University Children's Hospital. Patients were grouped according to the antimicrobials they received into a carbapenem group and a non-carbapenem group. Medical records were retrospectively reviewed to assess treatment outcome, time to defervescence after initiation of treatment, and relapse rate. Results: There were 36 children with 42 episodes of UTI caused by ESBL-producing Enterobacteriaceae. Twenty-seven cases (64%) had an underlying urologic disease, 28 (67%) cases were caused by Escherichia coil, and 14 (33%) cases were caused by Klebsiella pneumoniae. Four (10%) cases were treated with carbapenem, 23 cases (55%) were treated with non-carbapenem, and 15 (36%) cases were treated by switching from a carbapenem to a non-carbapenem and vice versa. There was no treatment failure at the time of antimicrobial discontinuation. Between the carbapenem and the non-carbapenem treatment groups, there were no significant differences in bacterial etiology (P=0.59), time to defervescence after the initiation of antimicrobials (P=0.28), and relapse rate (P=0.50). In vitro susceptibility to non-carbapenem antimicrobials did not affect the time to defervescence after the initiation of antimicrobial treatment, and the relapse rate in the non-carbapenem group. Conclusions: This study found no significant difference in the treatment outcome between pediatric patients treated with carbapenem and those treated with non-carbapenem antimicrobials for UTI caused by ESBL-producing Enterobacteriaceae. Therefore, the initially administered non-carbapenem can be maintained in UTI patients showing clinical improvement. [ABSTRACT FROM AUTHOR]

Purpose: Recent studies have established the association between hypotonic fluids administration and hospital-acquired hyponatremia in children. The present paper investigated the pattern of current practice in intravenous fluid prescription among Korean pediatric residents, to underscore the need for updated education. Methods: A survey-based analysis was carried out. Pediatric residents at six university hospitals in Korea completed a survey consisting of four questions. Each question proposed a unique scenario in which the respondents had to prescribe either a hypotonic or an isotonic fluid for the patient. Results: Ninety-one responses were collected and analyzed. In three of the four scenarios, a significant majority prescribed the hypotonic fluids (98.9%, 85.7%, and 69.2%, respectively). Notably, 69.2% of the respondents selected the hypotonic fluids for postoperative management. Almost all (96.7%) selected the isotonic fluids for hydration therapy. Conclusion: In the given scenarios, the majority of Korean pediatric residents would prescribe a hypotonic fluid, except for initial hydration. The current state of pediatric fluid management, notably, heightens the risk of hospital-acquired hyponatremia. Updated clinical practice education on intravenous fluid prescription is urgently required. [ABSTRACT FROM AUTHOR]

Background: Health-related quality of life is a very important issue in children with end-stage renal disease and their family. Moreover, this can be a lifelong problem. In this study, we performed a cross-sectional investigation of the health-related quality of life in Korean children, undergoing renal replacement therapies, such as dialysis and renal transplantation. Findings: We validated the Korean version of the PedsQL 3.0 End-Stage Renal Disease Module by comparing with the PedsQL 4.0 Generic Core Scales. A total of 92 pediatric patients with end-stage renal disease, aged 2-18 year old, were enrolled in four teaching hospitals in Korea. The module was acceptable for both parent proxy-report and child self-report. The response rate was acceptable, since no reminders were delivered. A large proportion of the responders answered >90% of the items, which suggests a good face validity. The PedsQL 4.0 Generic Core Scales and the PedsQL 3.0 End-Stage Renal Disease Module showed minimal missing values in the current study, which supported feasibility. The validation analyses revealed acceptable floor and ceiling effects and an acceptable construct validity. Conclusions: The PedsQL 3.0 End-stage Renal Disease Module may be useful as an end-stage renal disease -specific instrument in the evaluation of the health-related quality of life in Korean children; however, a larger, longitudinal prospective study is needed. [ABSTRACT FROM AUTHOR]

Recently, both embryonic stem cells and mesenchymal stem cells have been demonstrated to have immunosuppressive effects. The purpose of this study was to elucidate whether the embryonic stem cells and/or mesenchymal stem cells modulate both primary and secondary alloimmune responses. Both stem cells suppressed in vitro proliferation and cytokine production in primary alloimmune responses. They also suppressed in vitro proliferation and cytokine production of the allosensitized CD44+ memory T cells. However, they failed to prolong skin graft survival across both a major mismatch barrier (BALB/C, C57BL6/J) and a minor mismatch barrier (male to female). In conclusion, both embryonic stem cells and mesenchymal stem cells can suppress secondary alloimmune response in vitro as well as primary alloimmune responses; however, neither embryonic stem cells nor mesenchymal stem cells suppressed allograft rejection in stringent murine skin transplantation models. [ABSTRACT FROM AUTHOR]

Although technetium-99m-dimercaptosuccinic acid (99mTc-DMSA) renal scans are widely used to evaluate renal tubular mass function, the mechanism by which renal uptake of DMSA occurs is still the subject of debate. Patients with various proximal tubular disorders show markedly decreased renal DMSA uptake, even when there is normal creatinine clearance. We measured the renal uptake of 99mTc-DMSA 3 h after its injection in 13 patients with Dent disease or Lowe syndrome, both of which are typical proximal tubular disorders with defective megalin and cubilin-mediated endocytosis. Serial images of three patients were also obtained at 0.5, 1, 2 and 3 h post-injection. The correlations between renal uptake of 99mTc-DMSA and creatinine clearance and the degrees of acidemia and tubular proteinuria were then evaluated. The renal uptake of 99mTc-DMSA was markedly decreased in all patients, and the decreased uptake was detected in all serial images. In contrast, bladder radioactivity was higher than normal in all of the serial images when compared to renal radioactivity. Additionally, the uptake of 99mTc-DMSA was inversely proportional to the amount of urine β2-microglobulin. These results strongly suggest that DMSA is filtered in the glomeruli and subsequently undergoes megalin- and cubilin-mediated endocytosis in the proximal tubules. [ABSTRACT FROM AUTHOR]

To review the clinical course and identify prognostic factors, we retrospectively analyzed 92 children with steroid-resistant primary focal segmental glomerulosclerosis (FSGS). The mean age of onset was 80.4±42.4 months. The mean follow-up duration was 98.2±63.3 months. Eighty-five patients presented with nephrotic syndrome and seven presented with asymptomatic proteinuria. Thirty-three patients were initial responders to steroid treatment (late non-responders) and 59 were initial nonresponders. At last follow-up, 36 patients (39.1%) were in complete remission, and 29 (31.5%) progressed to chronic renal failure (CRF). Renal survival rates at 5, 10, and 15 years were 84, 64, and 53%, respectively. By morphological classification, there were tip variants (6.1%), collapsing variants (10.6%), cellular variants (1.5%), perihilar variants (9.1%), and NOS (not otherwise specified, 72.7%). Among the variants, there were no significant differences in age of onset, degree of proteinuria, response to treatment, or progression to CRF. Poor prognostic factors for CRF included: asymptomatic proteinuria at presentation, initial renal insufficiency, higher segmental sclerosis (%), severe tubulointerstitial change, initial nonresponse, and absence of remission. In the multivariate analysis, an increase in the initial serum creatinine and resistance to treatment were independent risk factors for CRF. A more prolonged use of corticosteroid therapy and early introduction of cyclosporin A (CsA) may improve the prognosis for primary FSGS in patients with initial steroid nonresponsiveness. [ABSTRACT FROM AUTHOR]

Idiopathic membranous nephropathy (MN) is a rare cause of asymptomatic proteinuria (AP) or nephrotic syndrome (NS) in childhood. To improve our understanding of its clinical course, we retrospectively reviewed 19 cases of idiopathic MN seen in our hospital over a period of 28.5 years, i.e., from January 1977 to July 2005. Eight patients (39%) had AP and 11 (61%) presented with NS. All eight AP patients achieved remission, regardless of treatment modality. Oral corticosteroid was given to all 11 NS patients, but only three of them responded to corticosteroid. Of the eight steroid non-responders, three achieved remissions with the addition of cyclosporine, and the five who were not administered additional immunosuppressive drugs had persistent NS. At the latest evaluation, all six NS patients that achieved remission remained free of proteinuria and had a normal renal function. Moreover, two of the 5 steroid non-responders showed persistent nephrotic-range proteinuria but a stable renal function. The remaining three steroid non-responders progressed into chronic renal insufficiency, and this progression was preceded by renal vein thrombosis (RVT) in two of the three patients. Presentation with NS ( P=0.045) and the development of RVT ( P=0.010) were identified as poor prognostic factors. [ABSTRACT FROM AUTHOR]

Dent’s disease is a hereditary renal tubular disorder caused by mutations of theCLCN5gene and is clinically characterized by low molecular weight proteinuria, hypercalciuria and nephrocalcinosis. This disease has been reported in several countries. However, there are some phenotypic differences between countries, such as hypophosphatemic rickets, progressive renal failure and hematuria. In this study, phenotypes were analyzed in three Korean boys with Dent’s disease, and genetic diagnoses were performed using a new convenient method using peripheral blood RNA. Gene studies revealed two nonsense mutations, R637X in two patients and E609X in one patient. The phenotypes of the two patients with R637X were very similar to those of Japanese patients, i.e., they presented with asymptomatic proteinuria without rickets, renal failure or hematuria. The E609X patient was diagnosed genetically at 3 months of age before the onset of clinical symptoms because of superimposed furosemide-induced nephrolithiasis. This is the first report to characterize mutations in theCLCN5gene in Korean patients with Dent’s disease, and expands the spectrum ofCLCN5mutations by reporting a novel mutation, E609X. In addition, the mutational analysis using peripheral blood RNA can be easily applied in the clinical diagnosis. [ABSTRACT FROM AUTHOR]

Complement factor H (FH) deficiency is one of the causes of atypical hemolytic uremic syndrome (HUS). Most patients with FH deficiency associated HUS progress to end-stage renal disease despite plasma therapy. Moreover, the disease invariably recurs in the graft kidney and causes graft failure. We confirmed FH deficiency in a 30-month-old boy with recurrent HUS of 2 years duration, and attempted an auxiliary partial orthotopic liver transplantation (APOLT) to overcome the sustained intractable dependency on plasma therapy. APOLT restored the plasma FH level, without HUS recurrence, for 7 months. However, thereafter he suffered from serious infectious complications associated with immunosuppression and finally died 11 months after APOLT. In conclusion, although APOLT showed clinical and laboratory improvement for some period in this patient, the final fatal outcome suggests that liver transplantation should be cautiously applied to patients with HUS associated with FH deficiency. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented about a study which investigates whether voiding cystoureterography (VCUG) is necessary for the diagnosis of vesicoureteral reflux (VUR) in infant boys with urinary tract infection (UTI).

Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury without any association with preceding diarrhea. Dysregulation of the complement system is the most common cause of aHUS, and monoclonal humanized anti-C5 antibodies are now recommended as the first-line treatment for aHUS. However, if the complement pathway is not the cause of aHUS, C5 inhibitors are ineffective. In this study, we report the second reported case of aHUS caused by DGKE mutations in Republic of Korea. The patient was an 11-month-old infant who presented with prodromal diarrhea similar to typical HUS, self-remitted with conservative management unlike complement-mediated aHUS but recurred with fever. While infantile aHUS often implies genetic dysregulation of the complement system, other rare genetic causes, such as DGKE mutation, need to be considered before deciding long-term treatment with C5 inhibitors. [ABSTRACT FROM AUTHOR]

Purpose: This article was to investigate the association between urinary tract infections (UTIs) and high weight status in infancy. Methods: We conducted a nationwide matched cohort study from January 2018 to December 2020 using data from the Korean National Health Insurance System and the Korean National Health Screening Program for Infants and Children. We analyzed the association between UTI diagnosis codes and high weight status (which was defined as being in the 90th percentile or higher of weight-for-age). Results: We found that 22.8% of infants with UTIs exhibited high weight status, compared to 20.0% of non-UTI infants (P<0.001). Per our multivariable analyses, the adjusted odds ratio for high weight status was 1.09 (95% confidence interval, 1.06-1.13). Conclusions: UTI in the first 12 months of life was associated with a weight-for-age percentile of =90. Our findings corroborate those of previous single-center studies and emphasize the importance of careful monitoring for this at-risk group. [ABSTRACT FROM AUTHOR]

Purpose: Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (ARBs) are frequently employed to counteract the detrimental effects of proteinuria on glomerular diseases. However, the effects of ARBs remain poorly examined in pediatric patients with immunoglobulin A (IgA) nephropathy. Herein, we evaluated the efficacy and safety of losartan, an ARB, in pediatric IgA nephropathy with proteinuria. Methods: This prospective, single-arm, multicenter study included children with IgA nephropathy exhibiting proteinuria. Changes in proteinuria, blood pressure, and kidney function were prospectively evaluated before and 4 and 24 weeks after losartan administration. The primary endpoint was the difference in proteinuria between baseline and 24 weeks. Results: In total, 29 patients were enrolled and received losartan treatment. The full analysis set included 28 patients who received losartan at least once and had pre- and post-urinary protein to creatinine ratio measurements (n=28). The per-protocol analysis group included 22 patients who completed all scheduled visits without any serious violations during the study period. In both groups, the mean log (urine protein to creatinine ratio) value decreased significantly at 6 months. After 24 weeks, the urinary protein to creatinine ratio decreased by more than 50% in approximately 40% of the patients. The glomerular filtration rate was not significantly altered during the observation period. Conclusions: Losartan decreased proteinuria without decreasing kidney function in patients with IgA nephropathy over 24 weeks. Losartan could be safely employed to reduce proteinuria in this patient population. [ABSTRACT FROM AUTHOR]

Purpose: This article was to collect data on the safety of coronavirus disease 2019 (COVID-19) vaccines in children with underlying medical conditions. Methods: We constructed a prospective cohort of children and adolescents aged 5 to 19 years who had received at least one dose of COVID-19 vaccine. Patients diagnosed with and treated for chronic kidney disease, autoimmune disease, or other chronic conditions at the Seoul National University Children's Hospital were recruited from June to December 2022. A mobile survey questionnaire was sent to their guardians. The presence of adverse events on the day (day 0), 3 weeks (day 21), and 6 months (day 180) after the 1st dose of COVID-19 vaccine was recorded by the guardians. Results: A total of 73 children participated. The median age was 14 years, and 64.4% of the patients were male. On the day of immunization, 65.8% of the patients reported at least one adverse event. Pain at the injection site, fatigue, headache, arthralgia, and myalgia were the most common symptoms. The prevalence of adverse events decreased over time (65.8% on day 0, 27.4% between days 0 and 21, and 24.6% between days 21 and 180). Severe acute respiratory syndrome coronavirus 2 infection after the 1st dose occurred in 17 patients (23.3%) and one of the patients (5.88%) was hospitalized due to infection. Conclusions: Adverse events after COVID-19 vaccination were generally mild in children and adolescents with underlying medical conditions. Our findings provide evidence for the safety of COVID-19 vaccination in the vulnerable pediatric population. [ABSTRACT FROM AUTHOR]

Purpose: Hematuria and proteinuria have various causes and consequential outcomes in children. Immunosuppressants are needed in some children with biopsy-proven glomerulonephropathy but have many adverse effects. Since the clinical practice patterns of Korean pediatric nephrologists are diverse, we surveyed their opinions. Methods: Using a clinical vignette, the survey was emailed to all Korean Society of Pediatric Nephrology members. The questionnaires included diagnosis, examination, medications, and dietary recommendations for patients with hematuria and proteinuria. Results: A total of 32 clinicians (5.48%, 22 pediatric certificated nephrologists) responded to the survey. Most responders (87.5%) suspected immunoglobulin A nephropathy, and 68.8% replied that kidney biopsies were a diagnostic tool. Renin-angiotensin system inhibition (62.5%) or steroids (18.8%) were selected as the treatment. Salt and protein intakes were usually encouraged as dietary reference intakes (34.4% and 65.6%, respectively). Conclusions: Children with abnormal urinalysis have various causes, treatments, and prognoses. As treatments such as immunosuppressants can have many adverse effects, it is necessary to confirm an accurate diagnosis and indications of treatments before starting the treatment. Recommendations for a diet should not hinder growth. [ABSTRACT FROM AUTHOR]

Although a severe shortage of organs in transplantation can be overcome by using xenotransplantation of porcine donor organs, profound immune rejection to xenogeneic antigens remains a main obstacle. To elucidate the role of hydrogen peroxide (H2O2) on xenogeneic immune responses, we investigated its effects on porcine aortic endothelial cells (PAECs). We found that H2O2 can specifically induce vascular cell adhesion molecule-1 (VCAM-1) expression on PAECs, but little on human umbilical vein endothelial cells (HUVECs) and aortic endothelial cells (HAECs). Furthermore, we further confirmed that H2O2 induces activation of NFκB in PAECs, but not in HAECs. Interestingly, cell adhesion assay showed that U937, human promonocytic leukocyte, can adhere to PAECs in an H2O2-dependent manner and by using a neutralizing assay with anti-VCAM-1-specific antibodies, we also found that the interaction is mediated primarily by VCAM-1. Finally, we also demonstrated that up-regulation of VCAM-1 expression on PAECs by reactive oxygen species-producing HL-60, human leukemic neutrophil cells, could be significantly diminished by over-expressing an H2O2-removing catalase. In summary, our results suggest that NFκB-dependent porcine VCAM-1 expression by H2O2 may promote interaction of human leukocyte to PAECs, and thus may play an important role on inducing xenogeneic immune responses. [ABSTRACT FROM AUTHOR]

This study analyzed survey results regarding awareness of living minors' organ donation. The questionnaires focused on changes in how respondents felt about donations by living minors after eliciting the uncertainty of long-term outcomes for living donors and recipients. The respondents were categorized asminors, adults affiliated with non-medical jobs (Non-Meds), and adults affiliated with medical jobs (Meds). The rates of awareness of living organ donation were significantly different; minors at 86.2%, non-Meds at 82.0%, and Meds at 98.7% (p < 0.001). Only 41.4% of Minors and 32.0% of Non-Meds were aware of organ donation by minors, while 70.3% of Meds were (p < 0.001). The response rate of opposition to organ donation by minors was highest for Meds and remained the same before and after (54.4%- 57.7%, p = 0.311). However, the opposition rate in Non-Meds significantly increased (32.4%-46.7%) after learning about the uncertainty of long-term outcomes (p = 0.009). The study found that Non-Meds lacked adequate knowledge regarding organ donation by minors and their potential lethal outcomes. Their attitudes toward organ donation by minors could be changed by giving structured information. It is necessary to provide exact information and raise social awareness regarding organ donation by living minors. [ABSTRACT FROM AUTHOR]

Purpose: Chronic kidney disease (CKD) has various underlying causes in children. Identification of the underlying causes of CKD is important. Genetic causes comprise a significant proportion of pediatric CKD cases. Methods: In this study, we performed whole-exome sequencing (WES) to identify genetic causes of pediatric CKD. From January to June 2021, WES was performed using samples from pediatric patients with CKD of unclear etiology. Results: Genetic causes were investigated using WES in 37 patients (17 males) with pediatric CKD stages 1 (n=5), 2 (n=7), 3 (n=2), 4 (n=2), and 5 (n=21). The underlying diseases were focal segmental glomerulosclerosis (n=9), congenital anomalies of the kidney and urinary tract including reflux nephropathy (n=8), other glomerulopathies (n=7), unknown etiology (n=6), and others (n=7). WES identified genetic causes of CKD in 12 of the 37 patients (32.4%). Genetic defects were discovered in the COL4A4 (n=2), WT1 (n=2), ACTN4, CEP290, COL4A3, CUBN, GATA3, LAMA5, NUP107, and PAX2 genes. WT1 defects were found in patients whose pathologic diagnosis was membranoproliferative glomerulonephritis, and identification of CUBN defects led to discontinuation of immunosuppressive agents. Genetic diagnosis confirmed the clinical diagnosis of hypoparathyroidism, sensorineural deafness, and renal disease; Alport syndrome; and Joubert syndrome in three of the patients with CKD of unknown etiology (COL4A4 [n=2], CUBN [n=1]). Extrarenal symptoms were considered phenotypic presentations of WT1, PAX2, and CEP290 defects. Conclusions: WES provided a genetic diagnosis that confirmed the clinical diagnosis in a significant proportion (32.4%) of patients with pediatric CKD. [ABSTRACT FROM AUTHOR]

C1q nephropathy is a rare glomerulopathy that typically presents with nephrotic syndrome in children. Treatment with immunosuppressive agents renders patients vulnerable to infection and its complications. Gastroenteritis is common in children, and rotavirus is a leading cause. Extraintestinal manifestations of rotavirus have recently been reported; however, there is a paucity of cases exploring the involvement of a rotavirus on the respiratory system. Acute respiratory distress syndrome (ARDS) is a rapid onset respiratory failure characterized by noncardiogenic pulmonary edema and hypoxemia. Causes of ARDS include sepsis, pneumonia, pancreatitis, aspiration, and trauma. In this paper, we report a case of ARDS after rotavirus infection in a child with C1q nephropathy who had been treated with immunosuppressive agents. [ABSTRACT FROM AUTHOR]

Chronic kidney disease (CKD)-mineral and bone disorder (CKD-MBD) is a common complication of CKD, often accompanied by extra-skeletal calcification in adult patients. As increased vascular calcification is predicted to increase cardiovascular mortality and morbidity, the revised Kidney Disease: Improving Global Outcomes guidelines recommend avoiding calcium-containing phosphate chelators. However, extra-skeletal calcification is less commonly noticed in pediatric patients. Here, we report our experience of such a complication in pediatric patients receiving maintenance peritoneal dialysis. Extra-skeletal calcification was noticed at the corneas, pelvic cavity, and soft tissues of the lower leg in 4 out of 32 patients on maintenance peritoneal dialysis. These patients experienced the aggravation of extra-skeletal calcifications during peritoneal dialysis, and 2 of them underwent excisional operations. It is required to monitor extra-skeletal calcifications in children on kidney replacement therapy. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the diagnostic performance of contrast-enhanced voiding urosonography (ce-VUS) using a second-generation ultrasound contrast agent for the diagnosis of vesicoureteral reflux (VUR) and intrarenal reflux (IRR), and compared it with that of standard fluoroscopic voiding cystourethrography (VCUG). Methods: Thirty-two consecutive children from April to October 2019 were included in this study. ce-VUS and VCUG were performed simultaneously by two operators with intravesical infusion of a mixture of ultrasound contrast medium, iodinated contrast medium and water. Two pediatric radiologists independently reviewed the ce-VUS and VCUG images and reported the presence and degree of VUR (grades I-V), and the presence and type of IRR. Results: Twenty-seven of 63 urinary systems showed VUR. Interobserver agreement for VUR grading was very good for both examinations (κ =0.87; 95% confidence interval [CI], 0.82 to 0.92 for ce-VUS and κ =0.92; 95% CI, 0.87 to 0.96 for VCUG). The detection rate of VUR showed no significant difference between the two examinations (P=0.370). Four cases of VUR were missed on ce-VUS, while one case of VUR was missed on VCUG. All four false-negative cases on ce-VUS were grade 1 VUR. The two examinations showed very good agreement regarding VUR grading (κ =0.89; 95% CI, 0.81 to 0.96). IRR was more frequently detected with ce-VUS than with VCUG (10 cases with ce-VUS vs. 3 cases with VCUG, P=0.016). Conclusion: ce-VUS showed very good agreement with VCUG for detecting grade 2 VUR and above, while grade 1 VUR was sometimes missed with ce-VUS. IRR was more frequently detected with ce-VUS than with VCUG. [ABSTRACT FROM AUTHOR]

Atypical hemolytic uremic syndrome (aHUS) is an extremely rare and life-threatening disorder. Typical HUS is often caused by Shiga toxin-positive Escherichia coli, while aHUS is caused by dysregulation of the alternative pathway of the complement system in association with genetic abnormalities or development of autoantibodies. Eculizumab, a humanized anti-complement 5 monoclonal antibody, is recommended for the treatment of aHUS, but its long-term safety and efficacy in pediatric patients remain under review. In this paper, we report a pediatric case of aHUS with anti-complement factor H autoantibodies, who was treated successfully with eculizumab. [ABSTRACT FROM AUTHOR]

Gorham-Stout syndrome is a rare bone disorder characterized by progressive massive osteolysis and proliferation of vascular and lymphatic vessels. A 15-yearold boy was initially diagnosed with Gorham-Stout at the age of 8 years based on clinical and radiological findings. Following diagnosis, he was treated with pamidronate, interferon alfa, propranolol, oral corticosteroids, and sirolimus. He developed proteinuria at the age of 15 and progressed into the nephrotic range 2 years later. A renal biopsy revealed focal segmental glomerulosclerosis, not otherwise specified variant. The sequential increase in proteinuria associated with medications suggested that the focal segmental glomerulosclerosis may be caused by pamidronate and sirolimus, but cannot completely rule out the possibility of kidney involvement of GSS itself. [ABSTRACT FROM AUTHOR]

Background: Primary hyperoxaluria (PH), a rare inborn error of glyoxylate meta bolism causing overproduction of oxalate, is classified into three genetic subgroups: type 1-3 (PH1-PH3) caused by AGXT, GRHPR, and HOGA1 gene mutations, respectively. We performed a retrospective case series study of Korean pediatric patients with PH. Methods: In total, 11 unrelated pediatric patients were recruited and their phenotypes and genotypes were analyzed by a retrospective review of their medical records. Results: Mutational analyses revealed biallelic AGXT mutations (PH1) in nine patients and a single heterozygous GRHPR and HOGA1 mutation in one patient each. The c.33dupC was the most common AGXT mutation with an allelic frequency of 44%. The median age of onset was 3 months (range, 2 months-3 years), and eight patients with PH1 presented with end stage renal disease (ESRD). Patients with two truncating mutations showed an earlier age of onset and more frequent retinal involvement than patients with one truncating mutation. Among eight PH1 patients presenting with ESRD, five patients were treated with intensive dialysis followed by liver transplantation (n=5) with/without subsequent kidney transplantation (n=3). Conclusion: Most patients presented with severe infantile forms of PH. Patients with two truncating mutations displayed more severe phenotypes than those of patients with one truncating mutation. Sequential liver and kidney transplantation was adopted for PH1 patients presenting with ESRD. A larger nation-wide multicenter study is needed to confirm the genotype-phenotype correlations and outcomes of organ transplantation. [ABSTRACT FROM AUTHOR]

The most common type of refractory hypertension found in children is secondary hypertension, which is a potentially curable disease. Reninoma, a renin-secreting juxtaglomerular cell tumor, is a rare cause of severe hypertension that is usually diagnosed in adolescents and young adults. Surgical resection of the tumor completely cures the hypertension of patients with reninoma. The typical clinical presentation of reninoma includes hypokalemia, metabolic alkalosis, and features secondary to the increased activation of the renin-angiotensin system without renal artery stenosis. We report a case of reninoma in a female adolescent with a typical clinical presentation, in which surgical removal of the tumor completely cured hypertension. We discuss here the clinical features, imaging studies, and immunohistochemical examination of the tumor used to establish the diagnosis of reninoma and for the management of the condition. [ABSTRACT FROM AUTHOR]

How can we predict the occurrence of acute kidney injury (AKI) in cancer patients based on machine learning with serum creatinine data? Given irregular and heterogeneous clinical data, how can we make the most of it for accurate AKI prediction? AKI is a common and significant complication in cancer patients, and correlates with substantial morbidity and mortality. Since no effective treatment for AKI still exists, it is important to take timely preventive measures. While several approaches have been proposed for predicting AKI, their scope and applicability are limited as they either assume regular data measured over a short hospital stay, or do not fully utilize heterogeneous data. In this paper, we provide an AKI prediction model with a greater applicability, which relaxes the constraints of existing approaches, and fully utilizes irregular and heterogeneous data for learning the model. In a cohort of 21,022 cancer patients who were registered into Korea Central Cancer Registry (KCCR) in Seoul National University Hospital between January 1, 2004 and December 31, 2013, our method achieves 0.7892 precision, 0.7506 recall, and 0.7576 F-measure in predicting whether a patient will develop AKI during the next 14 days.