Genotype-phenotype correlations in children with Gitelman syndrome.

BACKGROUND: This study aimed to analyze genotype-phenotype correlations in children with Gitelman syndrome (GS). METHODS: This multicenter retrospective study included 50 Korean children diagnosed with SLC12A3 variants in one or both alleles and the typical laboratory findings of GS. Genetic testing was performed using the Sanger sequencing except for one patient. RESULTS: The median age at the diagnosis was 10.5 years (interquartile range, 6.8;14.1), and 41 patients were followed up for a median duration of 5.4 years (interquartile range, 4.1;9.6). A total of 30 different SLC12A3 variants were identified. Of the patients, 34 (68%) had biallelic variants, and 16 (32%) had monoallelic variants on examination. Among the patients with biallelic variants, those (n = 12) with the truncating variants in one or both alleles had lower serum chloride levels (92.2 ± 3.2 vs. 96.5 ± 3.8 mMol/L, P = 0.002) at onset, as well as lower serum potassium levels (3.0 ± 0.4 vs. 3.4 ± 0.3 mMol/L, P = 0.016), and lower serum chloride levels (96.1 ± 1.9 vs. 98.3 ± 3.0 mMol/L, P = 0.049) during follow-up than those without truncating variants (n = 22). Patients with monoallelic variants on examination showed similar phenotypes and treatment responsiveness to those with biallelic variants. CONCLUSIONS: Patients with GS who had truncating variants in one or both alleles had more severe electrolyte abnormalities than those without truncating variants. Patients with GS who had monoallelic SLC12A3 variants on examination had almost the same phenotypes, response to treatment, and long-term prognosis as those with biallelic variants.

Genetic diagnosis of kidney disease by whole exome sequencing and its clinical application.

The genetic spectrum of genetic kidney diseases (GKD) and the application of genetic diagnoses to patient care were assessed by whole exome sequencing (WES) of the DNA of 172 pediatric or adult patients with various kidney diseases. WES diagnosed genetic diseases in 63 (36.6%) patients. The diagnostic yields in patients with glomerulopathy were 33.8% (25/74 pts) due to variants in 10 genes, 58.8% (20/34) in patients with tubulointerstitial disease due to variants in 18 genes, 33.3% (15/45) in patients with cystic disease/ciliopathy due to variants in 10 genes, 18.2% (2/11) in patients with congenital anomalies of the kidneys and urinary tract (CAKUT) due to variants in two genes, and 12.5% (1/8) in patients with end stage kidney disease (ESKD). The diagnosis rate was high in patients aged <1-6 years (46-50.0%), and low in patients aged ≥40 years (9.1%). Renal phenotype was reclassified in 10 (15.9%) of 63 patients and clinical management altered in 10 (15.9%) of 63 patients after genetic diagnosis. In conclusion, these findings demonstrated the diagnostic utility of WES and its effective clinical application in patients, with various kinds of kidney diseases, across the different age groups.

A child with crescentic glomerulonephritis following SARS-CoV-2 mRNA (Pfizer-BioNTech) vaccination.

BACKGROUND: There are few reports on kidney complications after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccination, especially in the pediatric population. We report a pediatric case diagnosed with crescentic glomerulonephritis (CrGN) after the second dose of the SARS-CoV-2 mRNA vaccine. CASE-DIAGNOSIS/TREATMENT: A 16-year-old girl was admitted due to dyspnea and headache approximately 6 weeks after receiving the second SARS-CoV-2 mRNA vaccine (Pfizer-BioNTech). She had previously experienced fever, nausea, vomiting, and dyspnea after the first vaccination, which persisted for a week. On admission, her blood pressure was 155/89 mmHg with a 7 kg weight gain in a month. She had microhematuria and proteinuria. Laboratory findings were as follows: blood urea nitrogen/creatinine, 66/9.57 mg/dL; and brain natriuretic peptide, 1,167 pg/mL. Anti-neutrophil cytoplasmic antibody (ANCA), anti-glomerular basement membrane (GBM) antibody, and antinuclear antibody findings were negative. Kidney doppler sonography revealed swelling and increased echogenicity of both kidneys with increased resistive index. Cardiac magnetic resonance imaging results showed early minimal fibrosis of myocarditis. We then started hemodialysis. Kidney biopsy showed diffuse extra capillary proliferative glomerulonephritis with diffuse crescent formation. We treated the patient with methylprednisolone pulse therapy with subsequent oral steroids and mycophenolate mofetil. Although dialysis was terminated, the patient remained in the chronic kidney disease stage. CONCLUSIONS: This is the first case of ANCA-negative CrGN after SARS-CoV-2 mRNA vaccination in the pediatric population. As children are increasingly vaccinated with SARS-CoV-2 mRNA vaccines, monitoring for kidney complications is warranted.

Association between serum total cholesterol and chronic kidney disease progression in children: results from the KNOW-PedCKD.

BACKGROUND: Dyslipidemia can cause cardiovascular disease and increase the fatality rate among children with chronic kidney disease (CKD); this makes early screening and treatment of dyslipidemia crucial. This study aimed to assess the association between the changes in serum total cholesterol levels over time and the degree of CKD progression in children. METHODS: From April 2011 to August 2021, 379 of the 432 participants enrolled in the KoreaN cohort study for Outcomes in patients With Pediatric CKD (KNOW-PedCKD) were included and divided into 4 categories based on total cholesterol levels (< 170 mg/dL, acceptable; 170-199, borderline; 200-239, high; and ≥ 240, very high). Survival analysis using conventional and time-dependent Cox proportional hazards model were performed for a composite event of CKD progression (≥ 50% decrease in estimated glomerular filtration rate from baseline, a twofold increase in creatinine, or the occurrence of dialysis or kidney transplantation). RESULT: The incidence of composite event of CKD progression was 96.3, 90.4, 87.3, and 270.6 cases per 1000 person-years in the acceptable, borderline, high, and very high categories, respectively. On using the time-dependent Cox proportional hazards model, the hazard ratio of the very high category was significantly higher than that of the acceptable category by 3.13 times as per univariate analysis and 2.37 times as per multivariate analysis. CONCLUSIONS: Very high serum total cholesterol is a significant risk factor for CKD progression in children. Lowering total cholesterol levels below the very high category in children with CKD may delay the progression of CKD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Kidney involvement in children during the SARS-CoV-2 Omicron variant pandemic.

BACKGROUND: As the coronavirus disease-2019 (COVID-19) pandemic continues, driven by the Omicron variant, infection rates in children have recently rapidly surged compared with previous years. We aimed to investigate the presentation of kidney involvement in children after Omicron variant severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. METHODS: We retrospectively reviewed the medical records of pediatric patients who presented with kidney disease with a temporal relationship with COVID-19 between January and August 2022 in a single tertiary center in Korea. RESULTS: Fifteen children presented with kidney involvement after Omicron variant infection, with a median age of 10.6 (6.8-18.3) years. None of the patients exhibited severe respiratory symptoms apart from cough and sore throat. The median time from infection to renal symptom onset was 3 (0-49) days. Among 10 patients with underlying kidney disease, six had previously been diagnosed with nephrotic syndrome (NS) that relapsed after COVID-19 infection, two with immunoglobulin A nephropathy (IgAN) experienced transient gross hematuria (GHU) with or without acute kidney injury (AKI), and two with kidney transplantation presented with AKI. Of the five patients without underlying kidney disease, one patient had NS, and the other four patients had GHU and proteinuria (PU), of whom one was eventually diagnosed with Henoch Shönlein Purpura nephritis (HSPN), and one with rhabdomyolysis. The seven patients with NS (1 new-onset, 6 relapsed) had uneventful remission with corticosteroid therapy. Apart from one patient with new-onset HSPN, GHU and PU resolved spontaneously in all affected patients, and AKI also resolved with supportive care. CONCLUSIONS: Kidney involvement subsequent to Omicron variant COVID-19 exhibited various, but mostly mild manifestations in children.

Baseline characteristics of participants enrolled in the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD).

BACKGROUND: We developed the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD) as a subcohort of KNOW-CKD to investigate the different characteristics of pediatric CKD between countries and races. METHODS: Children aged younger than 18 years with stage 1 ~ 5 CKD were recruited at seven major pediatric nephrology centers in Korea. Blood and urine samples, as well as demographic and clinical data, were collected. From 2011 to 2016, 458 children were enrolled, and the baseline profiles of 437 children were analyzed. RESULTS: The median age of the cohort was 10.9 years old, and 68.0% were males. The median estimated glomerular filtration rate was 53.1 mL/min/1.73 m2. The most common etiology of CKD was congenital anomalies of the kidney and urinary tract (42.6%), followed by glomerulopathies (25.6%). CONCLUSION: We report a cross-sectional analysis of the overall baseline characteristics such as age, CKD stage, and underlying kidney disease of the KNOW-Ped CKD. The cohort will be longitudinally followed for ten years. "A higher resolution version of the Graphical abstract is available as Supplementary information."

Incidence of and risk factors for short stature in children with chronic kidney disease: results from the KNOW-Ped CKD.

BACKGROUND: Preserving optimal growth has long been a significant concern for children with chronic kidney disease (CKD). We aimed to examine the incidence of and risk factors for short stature in Asian pediatric patients with CKD. METHODS: We analyzed growth status by height, weight, and body mass index (BMI) standard deviation scores (SDSs) for 432 participants in the KoreaN cohort study for Outcome in patients With Pediatric Chronic Kidney Disease. RESULTS: The median height, weight, and BMI SDSs were - 0.94 (interquartile range (IQR) - 1.95 to 0.05), - 0.58 (IQR - 1.46 to 0.48), and - 0.26 (IQR - 1.13 to 0.61), respectively. A high prevalence of short stature (101 of 432 patients, 23.4%) and underweight (61 of 432 patients, 14.1%) was observed. In multivariable logistic regression analysis, CKD stages 4 and 5 (adjusted odds ratio (aOR) 2.700, p = 0.001), onset before age 2 (aOR 2.928, p < 0.0001), underweight (aOR 2.353, p = 0.013), premature birth (aOR 3.484, p < 0.0001), LBW (aOR 3.496, p = 0.001), and low household income (aOR 1.935, p = 0.030) were independent risk factors associated with short stature in children with CKD. CONCLUSIONS: Children with CKD in Korea were shorter and had lower body weight and BMI than the general population. Short stature in children with CKD was most independently associated with low birth weight, followed by premature birth, onset before age 2, CKD stages 4 and 5, underweight, and low household income. Among these, underweight is the only modifiable factor. Therefore, we suggest children with CKD should be carefully monitored for weight, nutritional status, and body composition to achieve optimal growth.

Intellectual Functioning of Pediatric Patients with Chronic Kidney Disease: Results from the KNOW-Ped CKD.

BACKGROUND: Chronic kidney disease (CKD) has a negative impact on growth and development in children and is a risk factor for neurocognitive impairment; however, there is limited research on the cognitive function of children and adolescents with CKD. This study therefore aimed to investigate the mean intelligence and risk factors for low intelligence in children and adolescents with CKD. METHODS: Eighty-one patients with CKD under 18 years old were included in the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD). Participants completed either the Wechsler Intelligence Scale for Children (6-16 years), or Wechsler Adult Intelligence Scale (> 16 years). RESULTS: The mean full-scale intelligence quotient (IQ) was 91 ± 19; 24.7% of participants scored a full-scale IQ below 80. Participants with a short stature (height Z scores < -1.88), failure to thrive (weight Z scores < -1.65), more severe CKD stage (≥ IIIb), longer duration of CKD (≥ 5 years), and those who were Medicare or Medicaid beneficiaries, had significantly lower mean full-scale IQs. CONCLUSION: On linear regression analysis, the association between the full-scale IQ, and longer duration of CKD and growth failure, remained significant after controlling for demographic and clinical variables. It is therefore necessary to investigate cognitive impairment in pediatric patients with CKD who exhibit growth failure or for a longer postmorbid period. It is believed that early interventions, such as kidney transplantation, will have a positive effect on IQ in children with CKD, as the disease negatively affects IQ due to poor glomerular filtration rate over time. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02165878.

Utility of Society for Fetal Urology and Anteroposterior Pelvic Diameter Grading Systems for Estimating Time to Resolution of Isolated Hydronephrosis: A Single Center Study.

PURPOSE: We aimed to compare the Society for Fetal Urology and anteroposterior pelvic diameter classification systems in predicting the time to resolution of isolated hydronephrosis. MATERIALS AND METHODS: We retrospectively reviewed isolated hydronephrosis cases prenatally detected and postnatally diagnosed between 1994 and 2018. Other urinary tract anomalies and vesicoureteral reflux were excluded. Baseline grades for both systems were collected. Anteroposterior pelvic diameter was classified as grade 1 to 4 over a scale of 5 mm. Resolution was defined by an anteroposterior pelvic diameter of less than 5 mm with Society for Fetal Urology grade I hydronephrosis. Time to resolution was analyzed using Kaplan-Meier curves. RESULTS: The study population consisted of 831 patients (1,028 renal units). Median followup was 26 months (range 6 to 260), and 559 units (54.3%) reached resolution during a median followup of 9 months (1 to 133). Resolution rates at 48 months were 81.7%, 65.6%, 37.6% and 5.2% for Society for Fetal Urology grades I through IV disease and 80.0%, 41.2%, 13.1% and 2.5% for anteroposterior pelvic diameter grades 1 through 4, respectively. Discrepancies between these grades were present in 481 units (46.8%). Society for Fetal Urology grades II to IV categorized as anteroposterior pelvic diameter grade 1 showed a superior cumulative rate of resolution (84.7%) vs anteroposterior pelvic diameter grades 2 to 4 categorized as Society for Fetal Urology grade I (53.2%, log-rank test p <0.001). CONCLUSIONS: Hydronephrosis cases with anteroposterior pelvic diameter grades 2 to 4 but categorized as Society for Fetal Urology grade I have an inferior cumulative rate of resolution than vice versa. Society for Fetal Urology grades have little influence on resolution when anteroposterior pelvic diameter is less than 10 mm. Therefore, anteroposterior pelvic diameter is more useful in predicting the time to resolution.

Dyslipidemia in pediatric CKD patients: results from KNOW-PedCKD (KoreaN cohort study for Outcomes in patients With Pediatric CKD).

BACKGROUND: Pediatric as well as adult patients with chronic kidney disease (CKD) are susceptible to cardiovascular disease (CVD) events, which increase their mortality. Dyslipidemia is thought to be one of the most important contributing risk factors for developing CVD. This study aimed to evaluate the prevalence of dyslipidemia and assess clinical and laboratory risk factors associated with dyslipidemia in East Asian pediatric patients with CKD. METHODS: From April 2011 to April 2016, 469 patients with CKD aged < 20 years were enrolled in KNOW-PedCKD (the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease); 356 patients were included in the final analysis. Using the baseline data of the cohort cross-sectionally, a multivariable logistic regression analysis was performed to assess the risk factors for dyslipidemia; a subanalysis for each lipid abnormality was also done. RESULTS: The prevalence of dyslipidemia was 61.5% (n = 219). For dyslipidemia, nephrotic range proteinuria and 25-hydroxyvitamin D deficiency significantly increased the adjusted odds ratio. In the subanalysis, glomerulonephropathy as the origin of CKD and nephrotic range proteinuria significantly increased the risks for high total cholesterol and high low-density lipoprotein cholesterol. Overweight or obese body mass index z-score, elevated proteinuria, hypocalcemia, and 1,25-dihydroxyvitamin D deficiency were significantly associated with low high-density lipoprotein cholesterol. Glomerular filtration rate stage 3b or higher and hyperphosphatemia significantly increased the risk for high triglycerides. CONCLUSIONS: Long-term data accumulation and prospective analysis are needed to clarify the relationship between CKD progression and dyslipidemia and to find additional risk factors for dyslipidemia.

Challenges of acute peritoneal dialysis in extremely-low-birth-weight infants: a retrospective cohort study.

BACKGROUND: Peritoneal dialysis (PD) has been used occasionally in extremely-low-birth-weight (ELBW) infants with acute kidney injury (AKI). This study aimed to evaluate the clinical characteristics and outcomes of ELBW infants with AKI treated with PD. METHODS: In this retrospective cohort study, the medical records of ELBW infants with AKI, who underwent PD from January 2008 to February 2018, were reviewed. A PD catheter (7.5-9.0 Fr) or central venous catheter (4 Fr) was used for the peritoneal access. Treatment with PD solutions (2.5 or 4.25%) was started at 10 mL/kg, which was increased to 20-30 mL/kg for 60-120 min/cycle continuing for 24 h. RESULTS: Twelve ELBW infants (seven male and five female infants) were treated, and their mean (±SD) gestational age and birth weight were 27.2 (±3.3) weeks and 706.5 (±220.5) g, respectively. Two patients had severe perinatal asphyxia (5-min Apgar score ≤ 3). The most important indication for starting PD was AKI due to sepsis. The average (±SD) duration of PD was 9.4 (± 7.7) days. The potassium levels in the ELBW infants with hyperkalemia decreased from 6.8 to 5.0 mg/mL after 9.3 (± 4.4) days. The most common complication of PD was mechanical dysfunction of the catheters, such as dialysate leakage (75%). Two patients were successful weaned off PD. The mortality rate of the infants treated with PD was 91.7%. CONCLUSIONS: In this series, the mortality rate of ELBW infants with AKI treated with PD was relatively high because of their incompletely developed organ systems. Therefore, the use of PD should be carefully considered for the treatment of ELBW infants with AKI in terms of decisions regarding resuscitation.

Left-ventricular diastolic dysfunction in Korean children with chronic kidney disease: data from the KNOW-Ped CKD study.

BACKGROUND: Cardiovascular disease (CVD) is the most common cause of mortality in pediatric chronic kidney disease (CKD) patients. Left ventricular (LV) hypertrophy (LVH) is associated with LV diastolic dysfunction (LVDD) development and is used as an early marker of CVD in pediatric CKD. This study aimed to assess the prevalence and risk factors of LVDD and the association between LVH and LVDD in Korean pediatric CKD patients. METHODS: Data were collected using the baseline data of the Korean cohort study for outcome in patients with pediatric chronic kidney disease, a nationwide, 10-year, prospective, observational cohort study of pediatric CKD. A total of 244 patients were included in the final analysis. Two-dimensional echocardiography and tissue Doppler images were used to evaluate LVH and LVDD. LVH was defined as an LV mass index (LVMI) ≥38 g/m2.7 and LV-wall thickness z-score > 1.64. LVDD was defined as a mitral peak velocity of early filling to early diastolic mitral annular velocity (E/E') > 14. Univariate and multivariate logistic regression analyses were performed to evaluate risk factors of LVDD. RESULTS: In this study, the male-to-female ratio was 2.2 (168:76) and median age was 11.2 years. The average estimated glomerular filtration rate was 57.4 ml/min/1.73 m2, and no patients received renal replacement therapy. The mean value of LVMI and E/E' was 37.0 g/m2.7 and 7.4, respectively. The prevalence of LVH was 40.1 and 17.4% by LVMI ≥38 g/m2.7 and LV-wall thickness z-score, respectively. The prevalence of LVDD was 4.5%, and patients with LVH showed greater risk of LVDD (odds ratio 7.3, p = 0.012). In the univariate analysis, young age, low hemoglobin level, higher LVMI, and higher LV-wall thickness z-score were associated with LVDD. In the multivariate analysis, young age, low hemoglobin level, and higher LV-wall thickness z-score were independently associated with LVDD. CONCLUSION: This study shows that LVH patients have a greater risk of LVDD and that anemia is the only modifiable risk factor for LVDD in Korean pediatric CKD patients.

Mental health and psychosocial adjustment in pediatric chronic kidney disease derived from the KNOW-Ped CKD study.

BACKGROUND: Psychosocial development of pediatric chronic kidney disease (CKD) patients is substantially affected due to growth retardation, frequent school absences, and difficulties engaging in normal peer relationship activities. While many studies focus on specific issues such as depression, anxiety, or neurocognitive function, few evaluate prevalence of various types of mental health and psychosocial adjustment problems among children with CKD. This study aimed to investigate these within the KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease (KNOW-Ped CKD). METHODS: One hundred sixty-six subjects who completed the Korean-Child Behavioral Checklist (K-CBCL) were included. The clinical group comprised subjects with scores indicating psychosocial adjustment or mental health problems using the T scores for the 14 subscales of the K-CBCL. We analyzed associations between mental health or adjustment problems in pediatric CKD and each variable. RESULTS: Mean age was 11.1 (± 3.9) years, number of males was 117 (70.5%), and 20.5% and 22.3% of children had significant mental health problems and psychosocial adjustment problems, respectively. Overall, 33.1% were assigned to the clinical group, and exhibited short stature and higher rates of preterm birth history compared to the non-clinical group. Subjects with adjustment problems had higher comorbidities such as CNS disease, developmental delay, cardiovascular disease, and multi-organ involvement. Logistic regression analysis revealed preterm birth and developmental delay correlated highly with clinical group. CONCLUSIONS: A significant proportion of children and adolescents with CKD experience mental health and adjustment problems. In particular, patients with developmental delay or preterm birth history require screening and targeted follow-up.

B-type natriuretic peptide is a useful biomarker for the estimation of volume overload in children with hypertension on peritoneal dialysis.

AIM: The aim of the present study was to evaluate the usefulness of serum B-type natriuretic peptide (BNP) as a biomarker of fluid retention in hypertensive children on peritoneal dialysis (PD). METHODS: Hypertensive children on PD were included. The changes (∆) of body weight (BWt), blood pressure (BP) and serum BNP at initial and follow-up periods were reviewed. Data are presented as mean ± standard deviation (median, minimum - maximum). Wilcoxon signed-rank test was used to evaluate the changes in BWt, BP, and BNP. Linear regression analysis was applied for the correlation between the changes of BNP and BP. RESULTS: A total of 56 hypertensive events were evaluated in 30 patients. Initial findings were BWt 30.5 ± 22.4 (26.5, 3.0-93.5) kg, systolic BP (SBP) 153.3 ± 21.5 (150, 110-241) mmHg, diastolic BP (DBP) 100.1 ± 22.3, (99.5, 49-181) mmHg, BNP 3579.3 ± 6328.9 (1198.5, 305-22 028) pg/mL. Follow-up results were BWt 29.1 ± 21.3 (25.0, 3.12-86) kg, SBP 116.4 ± 17.8 (117.5, 82-150) mmHg, DBP 73.3 ± 14.2 (75.0, 42.0-101.0) mmHg, BNP 63.5 ± 49.2 (60.5, 2-261) pg/mL. ∆SBP (-23.1 ± 13.8, -22.8, -46.9 - 22.5%, P < 0.001), ∆DBP (-24.1 ± 19.2, -24.7, -55.6 - 23.2%, P < 0.001) and ∆BNP (-93.5 ± 8.1, -96.7, -99.9 - -61.0%, P < 0.001) dropped significantly after reduction of ∆BWt (-4.8 ± 4.7, -4.8, -18.7 - 5.6%, P < 0.001). The ∆BNP were significantly correlated with ∆SBP (adjusted R square = 0.221, P < 0.001) and ∆DBP (adjusted R square = 0.203, P < 0.001). CONCLUSIONS: Serum B-type natriuretic peptide should be measured in hypertensive patients on PD to evaluate the volume status.

Risk factors for persistent hyperparathyroidism in children with stable renal function after kidney transplantation.

This study aimed to investigate the risk factors for PHPT in children with stable renal function who received KT. We retrospectively analyzed the clinical findings and laboratory results of patients who underwent KT below 19 years of age, between 1996 and 2016 at our hospital. Patients were followed up for more than 1 year after KT. We calculated the mean ± standard deviation or median [minimum - maximum] for each parameter. We included a total of 46 patients (male:female = 26:20). Twelve patients (26.1%) were included in the PHPT group, and 34 (73.9%) were in the nPTH group. The dialysis duration was 57.1 ± 49.9, 44 [0-145] months in the PHPT group and 23.5 ± 25.8, 15 [1-121] months in the nPTH group (P = .040). The post-KT total CO2 level was significantly higher in the PHPT group (P = .022). The pre- (P = .021) and post-KT (P = .005) and 3-month average (P = .018) iPTH levels were also significantly higher in PHPT group. The height z-score showed a negative correlation, and the pre-KT, 3-month average phosphorus and alkaline phosphate levels showed positive correlations with iPTH levels, at 1 year after KT. Patients who undergo prolonged durations of dialysis, have increased iPTH levels before and after KT, and have low bicarbonate levels after KT are at risk of PHPT and should be monitored carefully.

Genotype-Phenotype Analysis in Pediatric Patients with Distal Renal Tubular Acidosis.

BACKGROUND/AIMS: Primary distal renal tubular acidosis (dRTA) in children is a rare genetic disorder, and three causative mutated genes have been identified: SLC4A1, ATP6V1B1, and ATP6V0A4. We analyzed the prevalence and phenotypic differences of genetic mutations in children with dRTA. METHODS: A total of 17 children with dRTA were enrolled in the study. All patients underwent genetic testing for all three candidate genes. RESULTS: Pathogenic mutations, including six novel mutations, were detected in 15 (88.2%) patients: dominant SLC4A1 mutations in ten (58.8%) patients, recessive ATP6V0A4 mutations in three (17.6%) patients, and recessive ATP6V1B1 mutations in two (11.8%) patients. Compared to other patients, patients with SLC4A1 mutations showed an older age of onset (3.7 ± 2.6 years) and less severe metabolic acidosis at initial presentation. All patients developed nephrocalcinosis, and sensorineural hearing loss was observed in two patients with ATP6V1B1 mutations. Three (17.6%) patients had decreased renal function (chronic kidney disease stage 2), and five (29.4%) patients had persistent growth retardation at the last follow-up. Long-term prognosis showed no genotype-phenotype correlation. CONCLUSIONS: SLC4A1 is the most common defective gene in Korean children with dRTA. Patients with SLC4A1 mutations show later onset and milder disease severity. Long-term follow-up of hearing ability, renal function, and growth is necessary for patients with dRTA.

Epstein-Barr virus infection in children with renal transplantation: A single-centre experience.

AIM: This study aimed to investigate the incidence, timing, manifestations, managements, and outcomes of Epstein-Barr virus (EBV) infection in paediatric renal transplant recipients in Korea. METHODS: We retrospectively evaluated 70 patients aged <18 years who had undergone renal transplantation between January 1990 and November 2014 at a single centre in Korea. EBV infection was diagnosed via serological test or real-time quantitative polymerase chain reaction (PCR). The diagnosis of post-transplant lymphoproliferative disorder (PTLD) was based on biopsy findings. RESULTS: In total, 21 patients (30.0% of renal transplant recipients) had EBV infection. EBV infection occurred at an average age of 12.6 ± 4.5 (median, 12.0; range, 7.0-24.0 years, with a mean period of 28.3 ± 27.2 (median, 14.0; range, 2.0-75.0) months for developing EBV infection after transplantation. EBV infection developed 12 times more frequently in pre-transplant EBV-seronegative recipients. Eight patients (38% of EBV-infected patients) had EBV disease, and six patients (75% of patients with EBV disease) had PTLD. The maximum EBV PCR titer was greater in patients with EBV disease than in the asymptomatic EBV infection group. The main treatment for EBV infection was the reduction in immunosuppressants. Asymptomatic EBV infection resolved in approximately 80% of the patients. One patient (17% of the patients with PTLD) expired. The glomerular filtration rate did not deteriorate during the treatment of EBV infection. CONCLUSION: Regular EBV monitoring in renal transplant recipients is mandatory for early diagnosis and treatment of EBV infections and prevention of PTLD, especially in pre-transplant EBV IgG-negative patients.

Impact of end-stage renal disease in children on their parents.

AIM: This study was designed to investigate the impact of paediatric end-stage renal disease (ESRD) on parents, based on the PedsQL Family Impact Module (FIM), and the relationship to the quality of life (QOL) of paediatric ESRD patients measured by PedsQL 3.0 ESRD module. METHODS: We performed a cross-sectional study using Korean translations of the PedsQL FIM and the PedsQL 3.0 ESRD module. In all, 79 patients were enrolled, including 47 children receiving dialysis and 32 children who underwent renal transplant. RESULTS: FIM scores, analyzed for every category according to treatment modality, were significantly lower in haemodialysis (HD) than in peritoneal dialysis (PD) or renal transplant patients. Mother's age, duration since diagnosis of ESRD and the existence of comorbidity were variables to have significant effects on FIM scores. The correlation between total FIM and QOL scores of paediatric patients were significant, in both parent-proxy and child-self report. CONCLUSIONS: The PedsQL FIM appears to be a useful tool for the assessment of family impact on children with ESRD. Further prospective studies focused on the QOL of parents and caregivers should be performed with the goal of improving clinical outcomes for paediatric ESRD patients.

Factors associated with reduction of left ventricular mass in children on peritoneal dialysis.

AIM: This study aimed to investigate sensitive factors involved in left ventricular mass reduction in children with end-stage renal disease (ESRD) undergoing peritoneal dialysis. METHODS: Thirty-five subjects on peritoneal dialysis were enrolled. Two successive echocardiographic and clinical data for each subject were obtained. Blood pressure and left ventricular mass index (LVMI) were indexed through a division with the normal 95th percentile value. Differences in numeric data between two datasets were calculated. RESULTS: The mean age was 12.9 ± 4.6 years. Predictors of left ventricular hypertrophy and its persistence were systolic blood pressure index (P = 0.019 and P = 0.046) and E' velocity (P = 0.035 and P = 0.031) in univariate analysis. However, differences in these predictors between the datasets were not related to the change in indexed LVMI. Reduction in indexed LVMI was correlated to a reduction of indexed left atrial volume (R = 0.638, P = 0.001), trans-mitral A velocity (R = 0.443, P = 0.011), and serum blood urea nitrogen level (R = 0.372, P = 0.028) and an elevation of haemoglobin level (R = -0.374, P = 0.027). CONCLUSION: The extent of circulating volume expansion is potentially the main predictive factor for change of LVMI, because the volume dependent diastolic functional variables correlate to the change of LVMI. Further study with a large number of ESRD children including a group under fluid volume control is needed to investigate the role of volume expansion on the change of LVMI.