Glomerular basement membrane ultrastructural changes in a patient with COQ2 glomerulopathy: A case report.

Primary coenzyme Q10 deficiency-1, caused by COQ2 disease-causing variants, is an autosomal recessive disorder, and genetic testing is the gold standard for diagnosing this condition. A Chinese boy with steroid-resistant nephrotic syndrome, focal segmental glomerulosclerosis, and progressive kidney insufficiency was included in the study. Electron microscopy revealed the glomerular basement membrane with irregular thickness and lamellation with diffuse effacement of foot processes in the podocytes, and swollen mitochondria with abnormal cristae in the podocytes. Coenzyme Q10 supplementation started about 3 weeks after the onset of mild kidney dysfunction did not improve the proband's kidney outcome. Proband-only whole-exome sequencing and Sanger sequencing revealed two heteroallelic COQ2 variants: a maternally inherited novel variant c.1013G > A[p.(Gly338Glu)] in exon 6 and a variant of unknown origin c.1159C > T[p.(Arg387*)] in exon 7. Subsequent long-read sequencing demonstrated these two variants were located on different alleles. Our report extends the phenotypic and genotypic spectrum of COQ2 glomerulopathy.

Are children with IgA nephropathy different from adult patients?

BACKGROUND: Previously, several studies have indicated that pediatric IgA nephropathy (IgAN) might be different from adult IgAN, and treatment strategies might be also different between pediatric IgAN and adult IgAN. METHODS: We analyzed two prospective cohorts established by pediatric and adult nephrologists, respectively. A comprehensive analysis was performed investigating the difference in clinical and pathological characteristics, treatment, and prognosis between children and adults with IgAN. RESULTS: A total of 1015 children and 1911 adults with IgAN were eligible for analysis. More frequent gross hematuria (88% vs. 20%, p < 0.0001) and higher proteinuria (1.8 vs. 1.3 g/d, p < 0.0001) were seen in children compared to adults. In comparison, the estimated glomerular filtration rate (eGFR) was lower in adults (80.4 vs. 163 ml/min/1.73 m2, p < 0.0001). Hypertension was more prevalent in adult patients. Pathologically, a higher proportion of M1 was revealed (62% vs. 39%, p < 0.0001) in children than in adults. S1 (62% vs. 28%, p < 0.0001) and T1-2 (34% vs. 8%, p < 0.0001) were more frequent in adults. Adjusted by proteinuria, eGFR, and hypertension, children were more likely to be treated with glucocorticoids than adults (87% vs. 45%, p < 0.0001). After propensity score matching, in IgAN with proteinuria > 1 g/d, children treated with steroids were 1.87 (95% CI 1.16-3.02, p = 0.01) times more likely to reach complete remission of proteinuria compared with adults treated with steroids. CONCLUSIONS: Children present significantly differently from adults with IgAN in clinical and pathological manifestations and disease progression. Steroid response might be better in children.

Histologic and Clinical Factors Associated with Kidney Outcomes in IgA Vasculitis Nephritis.

BACKGROUND: Nephritis is a common manifestation of IgA vasculitis and is morphologically indistinguishable from IgA nephropathy. While MEST-C scores are predictive of kidney outcomes in IgA nephropathy, their value in IgA vasculitis nephritis has not been investigated in large multiethnic cohorts. METHODS: Biopsies from 262 children and 99 adults with IgA vasculitis nephritis ( N =361) from 23 centers in North America, Europe, and Asia were independently scored by three pathologists. MEST-C scores were assessed for correlation with eGFR/proteinuria at biopsy. Because most patients ( N =309, 86%) received immunosuppression, risk factors for outcomes were evaluated in this group using latent class mixed models to identify classes of eGFR trajectories over a median follow-up of 2.7 years (interquartile range, 1.2-5.1). Clinical and histologic parameters associated with each class were determined using logistic regression. RESULTS: M, E, T, and C scores were correlated with either eGFR or proteinuria at biopsy. Two classes were identified by latent class mixed model, one with initial improvement in eGFR followed by a late decline (class 1, N =91) and another with stable eGFR (class 2, N =218). Class 1 was associated with a higher risk of an established kidney outcome (time to ≥30% decline in eGFR or kidney failure; hazard ratio, 5.84; 95% confidence interval, 2.37 to 14.4). Among MEST-C scores, only E1 was associated with class 1 by multivariable analysis. Other factors associated with class 1 were age 18 years and younger, male sex, lower eGFR at biopsy, and extrarenal noncutaneous disease. Fibrous crescents without active changes were associated with class 2. CONCLUSIONS: Kidney outcome in patients with biopsied IgA vasculitis nephritis treated with immunosuppression was determined by clinical risk factors and endocapillary hypercellularity (E1) and fibrous crescents, which are features that are not part of the International Study of Diseases of Children classification.

Machine learning in predicting T-score in the Oxford classification system of IgA nephropathy.

Background: Immunoglobulin A nephropathy (IgAN) is one of the leading causes of end-stage kidney disease (ESKD). Many studies have shown the significance of pathological manifestations in predicting the outcome of patients with IgAN, especially T-score of Oxford classification. Evaluating prognosis may be hampered in patients without renal biopsy. Methods: A baseline dataset of 690 patients with IgAN and an independent follow-up dataset of 1,168 patients were used as training and testing sets to develop the pathology T-score prediction (T pre) model based on the stacking algorithm, respectively. The 5-year ESKD prediction models using clinical variables (base model), clinical variables and real pathological T-score (base model plus T bio), and clinical variables and T pre (base model plus T pre) were developed separately in 1,168 patients with regular follow-up to evaluate whether T pre could assist in predicting ESKD. In addition, an external validation set consisting of 355 patients was used to evaluate the performance of the 5-year ESKD prediction model using T pre. Results: The features selected by AUCRF for the T pre model included age, systolic arterial pressure, diastolic arterial pressure, proteinuria, eGFR, serum IgA, and uric acid. The AUC of the T pre was 0.82 (95% CI: 0.80-0.85) in an independent testing set. For the 5-year ESKD prediction model, the AUC of the base model was 0.86 (95% CI: 0.75-0.97). When the T bio was added to the base model, there was an increase in AUC [from 0.86 (95% CI: 0.75-0.97) to 0.92 (95% CI: 0.85-0.98); P = 0.03]. There was no difference in AUC between the base model plus T pre and the base model plus T bio [0.90 (95% CI: 0.82-0.99) vs. 0.92 (95% CI: 0.85-0.98), P = 0.52]. The AUC of the 5-year ESKD prediction model using T pre was 0.93 (95% CI: 0.87-0.99) in the external validation set. Conclusion: A pathology T-score prediction (T pre) model using routine clinical characteristics was constructed, which could predict the pathological severity and assist clinicians to predict the prognosis of IgAN patients lacking kidney pathology scores.

Intraindividual variations of urinary biomarkers in hospitalized children with glomerular diseases: a prospective observational study.

This study aimed to assess the intraindividual variations of urinary biomarkers in hospitalized children with glomerular diseases. Hospitalized children with glomerular diseases participated in the study. For each patient, an overnight (9:00 p.m.-7:00 a.m.) urine was collected, followed by a 24-h urine (classified into four distinct periods: morning 7:00 a.m.-12:00 p.m., afternoon 12:00 p.m.-4:00 p.m., evening 4:00 p.m.-9:00 p.m., and overnight 9:00 p.m.-7:00 a.m.). The concentrations of protein, albumin, N-acetyl-beta-D-glucosaminidase, and epidermal growth factor (EGF) were measured and normalized by three correction factors (creatinine, osmolality, or specific gravity, respectively). Additionally, the 2nd overnight urine sample was grouped into different aliquots according to centrifugation, additives, storage temperature, or delayed processing. Twenty (14 boys, 6 girls) children were enrolled, with an average age of 11.3 years. Among the three correction factors, creatinine-normalized biomarkers provided the best agreements among different periods over 24 h. There were significant diurnal variations during 24 h in the concentrations of urinary protein, albumin, N-acetyl-beta-D-glucosaminidase, and EGF (p = 0.001, p = 0.003, p = 0.003, and p = 0.003, respectively). Evening urine overestimated 24-h urinary protein and albumin, while overnight urine underestimated 24-h urinary albumin. Urinary EGF showed low variability within a day or between the 2 days (coefficients of variation 10.2% and 10.6%, respectively) and excellent agreements (intraclass correlation coefficients > 0.9) with 24-h urinary concentration. Furthermore, urinary EGF was not affected by centrifugation, additives, storage temperature, or delayed processing of urine samples (all p > 0.05).  Conclusion: Given the diurnal variations of urinary biomarkers, urine samples should be collected during the same time period in clinical practice if possible. The results also extend the evidence for urinary EGF as a relatively stable biomarker applied in the future clinical practice. What is Known: • Urinary biomarkers have been widely used or discussed in making diagnoses and therapy regimens and estimating the prognosis of pediatric glomerular diseases. It remains unclear whether their levels would be affected by the time of sample collection, processing methods, and storage conditions in hospitalized children with glomerular diseases. What is New: • The levels of both commonly used biomarkers and novel biomarkers exhibited diurnal variations in hospitalized children with glomerular diseases. • Our results extend the evidence for urinary EGF as a relatively stable biomarker applied in the future clinical practice.

Urinary epidermal growth factor predicts complete remission of proteinuria in Chinese children with IgA nephropathy.

BACKGROUND: This study investigated the association between urinary epidermal growth factor (EGF) and complete remission (CR) of proteinuria in children with IgA nephropathy (IgAN). METHODS: We included 108 patients from the Registry of IgA Nephropathy in Chinese Children. The urinary EGF at the baseline and follow-up were measured and normalized by urine creatinine (expressed as uEGF/Cr). The person-specific uEGF/Cr slopes were estimated using linear mixed-effects models for the subset of patients with longitudinal data of uEGF/Cr. Cox models were used to analyze the associations of baseline uEGF/Cr and uEGF/Cr slope with CR of proteinuria. RESULTS: Patients with high baseline uEGF/Cr were more likely to achieve CR of proteinuria (adjusted HR 2.24, 95% CI: 1.05-4.79). The addition of high baseline uEGF/Cr on the traditional parameters significantly improved the model fit for predicting CR of proteinuria. In the subset of patients with longitudinal data of uEGF/Cr, high uEGF/Cr slope was associated with a higher likelihood of CR of proteinuria (adjusted HR 4.03, 95% CI: 1.02-15.88). CONCLUSIONS: Urinary EGF may be a useful noninvasive biomarker for predicting and monitoring CR of proteinuria in children with IgAN. IMPACT: High levels of baseline uEGF/Cr (>21.45 ng/mg) could serve as an independent predictor for CR of proteinuria. The addition of baseline uEGF/Cr on the traditional clinical pathological parameters significantly improved the fitting ability for the prediction of CR of proteinuria. Longitudinal data of uEGF/Cr were also independently associated with CR of proteinuria. Our study provides evidence that urinary EGF may be a useful noninvasive biomarker in the prediction of CR of proteinuria as well as monitoring therapeutic response, thus guiding treatment strategies in clinical practice for children with IgAN.

The spectrum and changes of biopsy-proven kidney diseases in Chinese children.

AIM: The study aimed to investigate the spectrum of biopsy-proven kidney disease in Chinese children. METHODS: Records of children 0-17 years old who underwent native kidney biopsy from June 1st, 2013 to December 31st, 2018 in the national inpatients' database of China were analyzed. Biopsy-proven kidney diseases of different sex, age groups, and diagnosis, and the changing patterns of kidney disease compared with the previous study were analyzed. RESULTS: A total of 21,311 patients from 232 hospitals with a median age of 11.34 years were included. Immunoglobulin A vasculitis with nephritis (IgAVN) was the most common pathological finding [29.17%, 95% confidence interval (confidence interval, CI) = 28.56-29.78], followed by IgA nephropathy (IgAN) (22.70%, 95% CI = 22.14-23.27). IgAN was the most common finding in patients with hematuria (60.75%, 95% CI = 58.83-62.65], proteinuria (33.43%, 95% CI = 30.54-36.42), and hematuria plus proteinuria (62.77%, 95% CI = 56.19-69.02). Minimal change disease was the most common finding (40.69%, 95% CI = 39.41-41.98) in nephrotic syndrome. The proportion of IgAVN in patients with biopsy-proven glomerular disease increased year by year during 2013-2018 (p for trend < 0.001) and was higher than that of 2004-2014 [29.41% (95% CI = 29.10-29.72) in 2013-2018 vs. 13.35% (95% CI = 12.97-13.73) 2004-2014, p < 0.001]. The proportion of hepatitis B virus associated nephritis during 2013-2018 was lower than that of  2004-2014 [0.44% (95% CI = 0.36-0.54) in 2013-2018 vs. 0.87% (95% CI = 0.67-1.10) in 2004-2014, p < 0.001]. CONCLUSIONS: IgAVN and IgAN were the most common types of pathological findings in children who underwent kidney biopsies from 2013 to 2018. The pathological spectrum of kidney biopsy changed over time.

Genotype and phenotype analysis and transplantation strategy in children with kidney failure caused by NPHP.

BACKGROUND: Nephronophthisis-related ciliopathies (NPHP-RC) have strong genotype and phenotype heterogeneity, and the transplantation strategy of Boichis syndrome is still controversial. Our purpose was to examine associations of genotype and phenotype in children with NPHP-RC and analyze the transplantation strategies of different phenotypes. METHODS: The records of children with NPHP treated at our center from 01/2018 to 03/2021 were retrospectively reviewed. Inclusion criteria were a diagnosis of NPHP, received kidney transplantation, and received whole exome sequencing (WES) or nephropathy gene panel testing. RESULTS: Twenty-nine children with NPHP were included. Nine children (31%) had NPHP1 mutations, and all presented with isolated nephropathy. Eighteen of 20 patients with non-NPHP1 mutations had compound heterozygous mutations, and 70% had extrarenal phenotype. Age at disease presentation (11.2 ± 1.94 years) and the development of kidney failure (12.4 ± 2.70 years) were later in children with NPHP1 mutations than those with non-NPHP1 mutations (5.2 ± 2.83 years and 5.7 ± 2.92 years, respectively). Four of six children with NPHP3 mutations were diagnosed with Boichis syndrome due to liver fibrosis. Isolated kidney transplantation resulted in good outcomes for patients with mild or moderate liver fibrosis without portal hypertension, while cholestasis was common postoperatively and could be resolved with ursodeoxycholic acid. CONCLUSIONS: NPHP1 mutations are the most common in children with NPHP, and the phenotype of NPHP1 mutation is significantly different from that of non-NPHP1 mutation. For NPHP patients with mild to moderate liver fibrosis without portal hypertension, timely treatment of cholestasis could prevent the rapid progression of liver function damage after isolated kidney transplantation. A higher resolution version of the Graphical abstract is available as Supplementary information.

Diagnosis and treatment of IgA nephropathy and IgA vasculitis nephritis in Chinese children.

IgA nephropathy (IgAN) and IgA vasculitis-associated nephritis (IgAVN) are among the most frequent childhood glomerular diseases and are characterized by significant variability in clinical manifestations, pathological presentation and long-term outcomes. IgAVN, alternatively called purpura nephritis, is pathologically indistinguishable from kidney-limited IgAN. In Chinese children, the clinical presentations and pathological manifestations of IgAN and IgAVN are variable. The severity of proteinuria and abnormalities in kidney function and blood pressure of children in China are comparable to those of children in Europe, the USA, and Japan. Compared to Caucasian children and Japanese children, crescents were more common in Chinese children with IgAN or IgAVN. Approximately 10-20% of childhood IgAN or IgAVN progresses to impaired kidney function in China. Since 2007, a series of guidelines on the diagnosis and treatment of pediatric kidney diseases has been published following the principles of evidence-based medicine. However, a large difference exists between the Chinese evidence-based guidelines and the guidelines developed by Kidney Disease: Improving Global Outcomes (KDIGO) in 2021. Chinese children with IgAN or IgAVN were more likely to be treated with steroids or immunosuppressive agents. Further studies exploring the optimal treatment regimen for childhood IgAN or IgAVN are needed in the future.

Integration of artificial intelligence and multi-omics in kidney diseases.

Kidney disease is a leading cause of death worldwide. Currently, the diagnosis of kidney diseases and the grading of their severity are mainly based on clinical features, which do not reveal the underlying molecular pathways. More recent surge of ∼omics studies has greatly catalyzed disease research. The advent of artificial intelligence (AI) has opened the avenue for the efficient integration and interpretation of big datasets for discovering clinically actionable knowledge. This review discusses how AI and multi-omics can be applied and integrated, to offer opportunities to develop novel diagnostic and therapeutic means in kidney diseases. The combination of new technology and novel analysis pipelines can lead to breakthroughs in expanding our understanding of disease pathogenesis, shedding new light on biomarkers and disease classification, as well as providing possibilities of precise treatment.

Incidence and cost of haemolytic uraemic syndrome in urban China: a national population-based analysis.

BACKGROUND: Haemolytic uraemic syndrome (HUS) is a severe syndrome that causes a substantial burden for patients and their families and is the leading cause of acute kidney injury in children. However, data on the epidemiology and disease burden of HUS in Asia, including China, are limited. We aimed to estimate the incidence and cost of HUS in China.  METHODS: Data about HUS from 2012 to 2016 were extracted from the Urban Employee Basic Medical Insurance (UEBMI) and Urban Resident Basic Medical Insurance (URBMI) databases. All cases were identified by ICD code and Chinese diagnostic terms. The 2016 national incidence rates were estimated and stratified by sex, age and season. The associated medical costs were also calculated. RESULTS: The crude incidence of HUS was 0.66 per 100,000 person-years (95% CI: 0.35 to 1.06), and the standardized incidence was 0.57 (0.19 to 1.18). The incidence of HUS in males was slightly higher than that in females. The age group with the highest incidence of HUS was patients < 1 year old (5.08, 95% CI: 0.23 to 24.87), and the season with the highest incidence was autumn, followed by winter. The average cost of HUS was 2.15 thousand US dollars per patient, which was higher than the national average cost for all inpatients in the same period. CONCLUSIONS: This is the first population-based study on the incidence of HUS in urban China. The age and seasonal distributions of HUS in urban China are different from those in most developed countries, suggesting a difference in aetiology.

Prominent renal complications associated with MMACHC pathogenic variant c.80A > G in Chinese children with cobalamin C deficiency.

Objective: CblC deficiency, the most common cobalamin metabolic abnormality, is caused by pathogenic variants in the MMACHC gene. The renal complications of this disease have been described only in a small number of cases. This study aimed to better delineate renal phenotype and genetic characteristics in Chinese children with cblC defect. Methods: Children with cblC deficiency who manifested as kidney damage were enrolled. Clinical, renal pathological, and genetic data were reviewed in detail. Results: Seven cases were enrolled. Ages at disease onset ranged from 9 months to 5 years. All patients presented with hematuria and proteinuria, and 2/7 cases presented with nephrotic syndrome. Renal dysfunction was observed in 4/7 cases. Renal biopsy was performed in 5/7 cases, and all of them had renal thrombotic microangiopathy. Macrocytic anemia was detected in all seven patients. Six out of seven cases had hypertension, and 2/7 cases presented with pulmonary hypertension. Two of them had a mild intellectual disability, and one suffered from epilepsy. Increased urine methylmalonic acid and plasma homocysteine were detected in seven cases, while two patients had normal levels of urine methylmalonic acid at the initial evaluation. After diagnosis, all seven cases were treated with hydroxocobalamin IM. Six cases were followed-up for 3-8 years. After treatments, anemia was the first to be recovered, followed by proteinuria. Renal function recovered after 1 year in two cases, whereas patient 2 progressed to stage 2 chronic kidney disease 13 years after onset. While a case presented with end-stage kidney disease because of late diagnosis, one case died 3 months after disease onset due to giving up treatment. Three MMACHC pathogenic variants c.80A > G (8/14), c.609G > A (4/14), and c.658_660delAAG (2/14) were detected in all seven children. Conclusion: MMACHC variant c.80A > G may be associated with prominent renal complications in Chinese cblC patients. Macrocytic anemia and hyperhomocysteinemia are useful clues for patients with hematuria and proteinuria caused by cblC defect. The most frequent renal pathological manifestation is thrombotic microangiopathy. Early diagnosis and treatment resulted in improving renal and hematological signs.

Glomerular C4d Deposition and Kidney Disease Progression in IgA Nephropathy: A Systematic Review and Meta-analysis.

BACKGROUND: Glomerular deposition of C4d is a widely used biomarker for activation of the lectin pathway in the complement system and is reported to be associated with kidney progression in immunoglobulin A nephropathy (IgAN). The aim of this study was to evaluate whether glomerular C4d deposition, as a new biomarker, improves the prediction of kidney prognosis in IgAN. STUDY DESIGN: Systematic review and meta-analysis. SETTING & POPULATION: Patients with biopsy-proven primary IgAN without age limitations.Selection Criteria for Studies: Cross-sectional or cohort studies reporting the prevalence of glomerular C4d deposition or evaluating its association with IgAN progression. PREDICTOR: Glomerular C4d deposition. OUTCOME: Composite progression event of a >30% decline in estimated glomerular filtration rate or end-stage kidney disease. RESULTS: 12 studies with 1,251 patients were included. The prevalence of glomerular C4d deposition was 34% (95% CI, 27%-41%), with large heterogeneity (I 2 = 86%; P < 0.001). Patients with C4d deposition had lower estimated glomerular filtration rates (mean difference [MD], -11.48; 95% CI, -18.27 to -4.70; P < 0.001) as well as higher urinary protein-creatinine ratios (MD, 0.87; 95% CI, 0.53-1.21; P < 0.001) or 24-hour urinary protein excretion (MD, 0.99; 95% CI, 0.50-1.47; P < 0.001) and higher risk for hypertension (relative risk [RR], 1.45; 95% CI, 1.06-1.99; P = 0.02) than patients without C4d deposition. Glomerular C4d deposition was associated with a high Oxford classification score, including M1, E1, S1, and T1/2 lesions (all P ≤ 0.006). Patients with C4d deposition had higher rates of use of renin-angiotensin system blockers and immunosuppressants. Glomerular C4d was found to be a risk factor for the composite kidney event (RR, 3.17; 95% CI, 2.29-4.40; P < 0.001; adjusted HR, 2.05; 95% CI, 1.53-2.76; P < 0.001) and end-stage kidney disease (RR, 4.37; 95% CI, 3.15-6.07; P < 0.001) without evidence of heterogeneity. LIMITATIONS: The definition of positive C4d was not uniform and not all studies provided data about kidney outcomes. CONCLUSIONS: Glomerular C4d deposition is associated with an adverse prognosis and may be a useful biomarker of disease prediction in IgAN.

Risk Factors for Progression of Chronic Kidney Disease With Glomerular Etiology in Hospitalized Children.

Aim: To Identify association between risk factors to Chronic kidney disease (CKD) stage 5 in children with glomerular diseases in children in China. Methods: The Hospital Quality Monitoring System database was used to extract data for the study cohort. The primary outcome included progression to CKD stage 5 or dialysis. Cox regression was used to assess potential risk factors. Patients with lower stages (CKD stage 1 and 2) and higher stages (CKD stage 3 and 4) at baseline were analyzed separately. Results: Of 819 patients (4,089 hospitalization records), 172 (21.0%) patients reached the primary outcome during a median followed-up of 11.4 months. In the lower stages group, factors associated with the primary outcome included older age [Hazard Ratio (HR), 1.21; 95% confidence interval (CI), 1.10-1.34] and out-of-pocket payment (HR, 4.14; 95% CI, 1.57-10.95). In the higher stages group, factors associated with the primary outcome included CKD stage 4 (HR, 2.31; 95% CI, 1.48-3.62) and hypertension (HR, 1.99; 95% CI, 1.29-3.07). The medical migration rate was 38.2% in this study population. Conclusion: There are different risk factors for progression to the primary outcome in different stages in CKD with glomerular etiology. Further prospective studies are needed to assess these risk factors. The high medical migration rate reflected the regional disparities in the accessibility of pediatric kidney care between regions.

Spectrum of Mutations in Pediatric Non-glomerular Chronic Kidney Disease Stages 2-5.

Renal hypodysplasia and cystic kidney diseases, the common non-glomerular causes of pediatric chronic kidney disease (CKD), are usually diagnosed by their clinical and imaging characteristics. The high degree of phenotypic heterogeneity, in both conditions, makes the correct final diagnosis dependent on genetic testing. It is not clear, however, whether the frequencies of damaged alleles vary among different ethnicities in children with non-glomerular CKD, and this will influence the strategy used for genetic testing. In this study, 69 unrelated children (40 boys, 29 girls) of predominantly Han Chinese ethnicity with stage 2-5 non-glomerular CKD caused by suspected renal hypodysplasia or cystic kidney diseases were enrolled and assessed by molecular analysis using proband-only targeted exome sequencing and array-comparative genomic hybridization. Targeted exome sequencing discovered genetic etiologies in 33 patients (47.8%) covering 10 distinct genetic disorders. The clinical diagnoses in 13/48 patients (27.1%) with suspected renal hypodysplasia were confirmed, and two patients were reclassified carrying mutations in nephronophthisis (NPHP) genes. The clinical diagnoses in 16/20 patients (80%) with suspected cystic kidney diseases were confirmed, and one patient was reclassified as carrying a deletion in the hepatocyte nuclear factor-1-beta gene (HNF1B). The diagnosis of one patient with unknown non-glomerular disease was elucidated. No copy number variations were identified in the 20 patients with negative targeted exome sequencing results. NPHP genes were the most common disease-causing genes in the patients with disease onsets above 6 years of age (14/45, 31.1%). The children with stage 2 and 3 CKD at onset were found to carry causative mutations in paired box gene 2 (PAX2) and HNF1B gene (11/24, 45.8%), whereas those with stage 4 and 5 CKD mostly carried causative mutations in NPHP genes (19/45, 42.2%). The causative genes were not suspected by the kidney imaging patterns at disease onset. Thus, our data show that in Chinese children with non-glomerular renal dysfunction caused by renal hypodysplasia and cystic kidney diseases, the common causative genes vary with age and CKD stage at disease onset. These findings have the potential to improve management and genetic counseling of these diseases in clinical practice.

Factors predicting the recovery from acute kidney injury in children with primary nephrotic syndrome.

BACKGROUND: The prognosis of acute kidney injury (AKI) varies in children with nephrotic syndrome (NS), data on factors predicting the recovery and recurrence of AKI in children with NS are limited. This study aimed to explore the possible factors predicting the recovery from and recurrence of AKI in children with primary NS. METHODS: Children with primary NS complicated with AKI from 1993 to 2017 in a single centre were reviewed retrospectively. The clinical pictures and possible factors predicting the recovery from and recurrence of AKI in children with primary NS were investigated. RESULTS: Sixty-eight episodes of AKI in 59 children with NS were analysed: 88.2% of AKI recovered within 3 months, and 2.9% of AKI did not recover after 3 months. Survival analysis revealed that leucocyturia is significantly related to the AKI recovery time (P = 0.001), and children with leucocyturia [22 (4, 79) days] recovered significantly slower than did children without leucocyturia [12.0 (2, 39) days]. Renal tubular and interstitial injury were prominent in children with leucocyturia, and 11.9% of children with index AKI experienced the recurrence of AKI. CONCLUSIONS: Most episodes of AKI that occurred in children with NS recovered completely. Leucocyturia is a significant factor predicting the recovery time of AKI.

Analysis of chronic kidney disease among national hospitalization data with 14 million children.

BACKGROUND: The main purpose was to determine basic epidemiological data on CKD among hospitalized pediatric patients in China. METHODS: Data from pediatric inpatients with CKD hospitalized from June 1, 2013 to May 31, 2017 were extracted from the electronic records of HQMS database, which includes over 14 million inpatients. Codes from the 10th revision of the International Classification of Diseases (ICD-10) were used to search the database. RESULTS: A total of 524 primary diseases of CKD were included in this study. In all, there were 278 231 pediatric inpatients with CKD, which accounted for 1.95 % of the 14 250 594 pediatric inpatients registered in the HQMS database. The number of pediatric inpatients with CKD was 67 498 in 2013, 76 810 in 2014, 81 665 in 2015 and 82 649 in 2016, which accounted for 1.93 %, 1.93 %, 1.99 and 2.09 %, respectively, of the total population of pediatric inpatients. The etiology of CKD was secondary nephrosis in 37.95 % of cases, which ranked first and followed by CAKUT with a percentage of 24.61 %. Glomerular diseases and cystic kidney disease accounted for 21.18 and 5.07 %, respectively. Among all 278 231 patients, 6 581 (2.37 %) had a primary discharge diagnosis of CKD. The renal pathology findings of CKD showed that IgA accounted for 51.17 %. CONCLUSIONS: This study provides a descriptive analysis of the hospitalized population of pediatric CKD patients. Our study provides important, fundamental data for policy making and legislation, registry implementation and the diagnosis, treatment and prevention of CKD in China.

Risk Factors Associated With Abnormal Urinalysis in Children.

Background: Targeted urinalysis has been suggested to improve screening efficiency in adults. However, there is no well-defined target population in children yet, with limited information on the risk factors for urinalysis abnormalities. Methods: Children from infants to 17 years old were randomly selected. Dipstick urinalysis was initially performed. Among those who were abnormal, a repeat dipstick or dipstick with microscopic urinalysis was performed for confirmation. Results: In total, 70,822 children were included, with 37,866 boys and 32,956 girls. Prevalence of abnormal urinalysis was 4.3%. Age was significantly associated with abnormal urinalysis, with the highest prevalence among 12-14-year-olds. Girls were 2.0 times more likely to exhibit abnormalities. Compared with children whose guardians had a college degree or higher, those whose guardians had a high school degree or lower had a higher likelihood of abnormalities. Geographic location was also associated with abnormal results. Conclusion: Girls, children aged 12-14 years old, and children whose guardians had a low educational level and children in certain geographic locations were significantly associated with abnormal urinalysis. Identification of children at high risk would contribute to targeted urinalysis screening.

Spectrum of thrombotic complications and their outcomes in Chinese children with primary nephrotic syndrome.

BACKGROUND: Thromboembolism is a life-threatening, limb-threatening or organ-threatening complication that occurs in patients with primary nephrotic syndrome (NS). There are few studies on the spectrum, complications and outcomes of thrombosis in children with NS. This study aimed to determine the spectrum of thrombosis and its relationship with the nephrotic state, treatment and outcomes in children and adolescents with primary NS. METHODS: The medical records of subjects aged 1-18 years with NS complicated with thromboembolism treated at our centre within the last 26 years were retrieved. Data on the status of NS, site, symptoms and signs, laboratory investigations, diagnosis, treatment, complications and outcomes of thrombosis were collected and reviewed retrospectively. A severe complication was defined as a condition associated with thrombosis requiring a special diagnostic modality to confirm or a specific treatment such as surgical intervention. The outcome of thrombosis was defined as the status of thrombosis, as determined by imaging methods and the functional status with respect to the anatomic sites of thrombosis at the last follow-up. The permanent dysfunction of an organ or limb related to thrombosis was defined as a sequela. RESULTS: We observed thrombosis in 1.4% (27/1995) of subjects with NS during the study period. There were 27 subjects with thrombosis, including 21 males and 6 females. Thrombosis was observed in 51.9% (14/27) of the study participants with steroid resistant NS. Most episodes of thrombosis occurred during the active stage of NS; however, 7.4% of thrombosis cases occurred during the remission of proteinuria. Renal vein thrombosis (33.3%) and pulmonary embolism (25.9%) were the most common types of thrombosis. Among the 17 subjects biopsied, minimal change disease and membranous nephropathy were the two most common findings. Six (22.2%) subjects experienced severe complications or sequelae; 1 had persistent intracranial hypertension, 1 had intestinal perforation, 1 had hypoxemia and pulmonary hypertension, 1 had lameness, 1 had epilepsy, and 1 had an askew mouth due to facial paralysis. In 19 (70.4%) subjects, the symptoms resolved completely or improved without severe complications or sequelae. CONCLUSIONS: Thrombosis mostly occurred in males of school age during the active stage of NS. Renal vein thrombosis and pulmonary embolism were the most common types of thrombosis. In most patients with thrombosis, the symptoms improved completely without complications with standard anticoagulation therapy. However, 22.2% had severe complications or sequelae requiring an advanced diagnostic modality and aggressive treatment.

[Efficacy and safety of steroid combined with immunosuppressants in the treatment of primary IgA nephropathy in children: a Meta analysis].

OBJECTIVE: To systematically evaluate the efficacy and safety of steroid combined with immunosuppressants in the treatment of primary IgA nephropathy in children. METHODS: English and Chinese electronic databases were searched to include the studies on the efficacy and safety of steroid combined with immunosuppressants versus steroid alone in the treatment of primary IgA nephropathy in children. Outcome measures included proteinuria remission rate, urinary protein quantification, incidence of adverse events, estimated glomerular filtration rate, and incidence of renal dysfunction. Review Manager 5.3 software was used for data analysis. RESULTS: A total of 7 studies with 381 children were included. The children had moderate to severe proteinuria. The Meta analysis showed that compared with the steroid alone group, the steroid combined with immunosuppressants group achieved a significantly higher rate of proteinuria remission (RR=1.36, 95%CI: 1.19-1.55, P<0.001) and significantly lower urinary protein quantification (SMD=-0.82, 95%CI: -1.23 to -0.41, P<0.001). There was no significant difference in the incidence rate of adverse events between the two groups (RR=1.28, 95%CI: 0.92-1.77, P=0.14). CONCLUSIONS: The current evidence shows that for children with primary IgA nephropathy who have moderate to severe proteinuria, steroid combined with immunosuppressants has a better effect than steroid alone and does not increase the incidence rate of adverse events.