Pediatric kidney disease has a relatively lower prevalence than do other pediatric conditions and has a notably different etiology from kidney diseases observed in adults. Furthermore, the pediatric population is unique in that they experience ongoing growth and development, distinguishing them from adult patients. Consequently, pediatric patients with kidney disease require more specialized and meticulous nutritional management than do adults. To address this need and promote optimal dietary practices for pediatric patients with kidney disease, pediatric nephrologists from the Korean Society of Pediatric Nephrology and nutritionists from the Korean Society of Clinical Nutrition have collaborated to establish nutritional guidelines specifically tailored to Korean dietary patterns. These guidelines offer detailed, nutrient-specific recommendations covering energy, protein, calcium, phosphorus, and potassium consumption while providing practical, culturally relevant guidance intended to support both pediatric patients and their caregivers.

Pediatric nephrotic syndrome is a clinical condition characterized by severe proteinuria, hypoalbuminemia, hyperlipidemia, and generalized edema, most commonly affecting children aged 2 and 6 years. Although standard oral steroid therapy is effective in managing most cases, relapses are common during childhood. Nephrotic syndrome presents significant challenges due to frequent relapses and the potential side effects of long-term drug therapy. In Korea, the absence of a unified national clinical guideline has led physicians to manage pediatric nephrotic syndrome based on diverse clinical guidelines and individual clinical judgment. To address this, the Korean Society of Pediatric Nephrology has developed an evidence-based guideline specifically tailored to the Korean healthcare system. This guideline provides recommendations for the diagnosis and management of steroid-sensitive nephrotic syndrome in children under the age of 18 years.

The natural course of chronic kidney disease (CKD) progression in children varies according to their underlying conditions. This study aims to identify different patterns of subsequent decline in kidney function and investigate factors associated with different patterns of estimated glomerular filtration rate (eGFR) trajectories. Methods: We analyzed data from the KNOW-Ped CKD (KoreaN cohort study for Outcomes in patients With Pediatric Chronic Kidney Disease), which is a longitudinal, prospective cohort study. A latent class linear mixed model was applied to identify the trajectory groups. Results: In a total of 287 patients, the median baseline eGFR (mL/min/1.73 m2) was 63.3, and the median age was 11.5 years. The eGFR decline rate was –1.54 during a 6.0-year follow-up. The eGFR trajectory over time was classified into four groups. Classes 1 (n = 103) and 2 (n = 11) had a slightly reduced eGFR at enrollment with a stable trend (ΔeGFR, –0.2/year) and a rapid decline eGFR over time (ΔeGFR, –10.5/year), respectively. Class 3 had a normal eGFR (n = 16), and class 4 had a moderately reduced eGFR (n = 157); both these chasses showed a linear decline in eGFR over time (ΔeGFR, –4.1 and –2.4/year). In comparison with classes 1 and 2, after adjusting for age, causes of primary renal disease, and baseline eGFR, nephrotic-range proteinuria was associated with a rapid decline in eGFR (odds ratio, 8.13). Conclusion: We identified four clinically relevant subgroups of kidney function trajectories in children with CKD. Most children showed a linear decline in eGFR; however, there are different patterns of eGFR trajectories.

This study investigated the clinical characteristics and kidney outcomes of childhood-onset lupus nephritis (LN), and risk factors associated with prognosis. Methods: We enrolled 216 patients with histologically diagnosed LN during childhood. The Korean Society of Pediatric Nephrology organized a retrospective cohort study of childhood-onset LN in 13 major pediatric nephrology centers in South Korea. Results: The mean age at kidney biopsy was 13.2 ± 3.22 years. The main forms of presentation were nephrotic syndrome and/or hematuria in 152 patients (70.4%), and the most common histological finding was World Health Organization (WHO) class IV in 138 patients (63.9%), followed by WHO class III in 34 patients (15.7%). In the outcome analysis, the mean follow-up period of the patients was 7.8 ± 5.11 years. At last follow-up, 32 patients (14.8%) developed advanced chronic kidney disease (CKD). Male sex and failure to achieve remission at 12 months of treatment were significant risk factors for developing advanced CKD (hazard ratio of 2.57 and 2.29, respectively). Conclusion: Our study demonstrated the clinical characteristics and long-term outcomes of patients with childhood-onset LN. Male sex and failure to achieve remission in the first year of treatment were predictive of advanced CKD. Therefore, prompt awareness and close monitoring of these high-risk patients are needed, which may further improve the prognosis of children with LN.

Pediatric kidney disease has a relatively lower prevalence than do other pediatric conditions and has a notably different etiology from kidney diseases observed in adults. Furthermore, the pediatric population is unique in that they experience ongoing growth and development, distinguishing them from adult patients. Consequently, pediatric patients with kidney disease require more specialized and meticulous nutritional management than do adults. To address this need and promote optimal dietary practices for pediatric patients with kidney disease, pediatric nephrologists from the Korean Society of Pediatric Nephrology and nutritionists from the Korean Society of Clinical Nutrition have collaborated to establish nutritional guidelines specifically tailored to Korean dietary patterns. These guidelines offer detailed, nutrient-specific recommendations covering energy, protein, calcium, phosphorus, and potassium consumption while providing practical, culturally relevant guidance intended to support both pediatric patients and their caregivers.

Persistent proteinuria is an important indicator of kidney damage and requires active evaluation and intervention. However, tubular proteinuria of genetic origin typically does not improve with immunosuppression or antiproteinuric treatment. Recently, defects in CUBN were found to cause isolated proteinuria (mainly albuminuria) due to defective tubular albumin reuptake. Unlike most other genetically caused persistent albuminuria, CUBN C-terminal variants have a benign course without progression to chronic kidney disease according to the literature. Here, we present Korean cases with persistent proteinuria associated with C-terminal variants of CUBN. Methods: We identified Korean patients with CUBN variants among those with an identified genetic cause of proteinuria and evaluated their clinical features and clinical course. We also reviewed the literature on CUBN-associated isolated proteinuria published to date and compared it with Korean patients. Results: All patients presented with incidentally found, asymptomatic isolated proteinuria at a median age of 5 years. The proteinuria was in the subnephrotic range and did not significantly change over time, regardless of renin- angiotensin system inhibition. Initial physical examination, laboratory findings, and kidney biopsy results, when available, were unremarkable other than significant proteinuria. All patients maintained kidney function throughout the follow-up duration. All patients had at least one splicing mutation, and most of the variants were located C-terminal side of the gene. Conclusion: We report Korean experience of CUBN-related benign proteinuria, that aligns with previous reports, indicating that this condition should be considered in cases with incidentally found asymptomatic isolated proteinuria, especially in young children.

Little is known about the transgenerational effects of maternal exposure to fine particulate matter (PM2.5) on offspring kidney health. This study investigated the effect of maternal administration of PM2.5 or PM2.5 with vitamin D during pregnancy and lactation on renal injury in rat dams and their offspring. Methods: Nine pregnant Sprague-Dawley rats received oral administration of normal saline, airborne PM2.5, or PM2.5 with vitamin D from gestational day 11 to postpartum day 21. Kidneys of rat dams (n = 3 for each group) and their male offspring (n = 5 for each group) were taken for analysis on postpartum or postnatal day 21. Results: Maternal PM2.5 exposure increased glomerular damage, tubulointerstitial injury, and cortical macrophage infiltration in both dams and pups; all increases were attenuated by vitamin D administration. In dam kidneys, PM2.5 increased the protein expression of vitamin D receptor (VDR), klotho, and tumor necrosis factor-α; vitamin D lessened these changes. The expressions of renin, nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear factor-kappa B (NF-κB) p50 decreased in rat dams exposed to PM2.5. In offspring kidneys, exposure to maternal PM2.5 reduced the expression of VDR, renin, angiotensin-converting enzyme (ACE), Nrf2, and NF-κB p50, but increased cytochrome P450 24A1 expression. Maternal vitamin D administration with PM2.5 enhanced VDR, ACE, and NF-κB p50 activities in pup kidneys. Conclusion: PM2.5 exposure during nephrogenesis may exert transgenerational renal impairment, and maternal vitamin D intake could attenuate PM2.5-induced kidney damage in mothers and their offspring.

Hematuria is a relatively common condition among school-aged children. Because international guidelines for asymptomatic hematuria in children are unavailable, developing practical guidelines for the diagnosis and management of asymptomatic hematuria based on scientific evidence while considering real-world practice settings, values, and patient and physician preferences is essential. The Korean Society of Pediatric Nephrology developed clinical guidelines to address key questions regarding the diagnosis and management of asymptomatic hematuria in children.

Hematuria is the presence of blood in the urine and is classified as either gross hematuria or microscopic hematuria. There are many causes of hematuria, and the differential diagnosis depends on the presence or absence of comorbidities and whether it is glomerular or non-glomerular. When hematuria in children is symptomatic or persistent, an evaluation of the cause is essential. The causes of hematuria and basic approaches to its diagnosis are discussed in this review.

Persistent proteinuria is an important indicator of kidney damage and requires active evaluation and intervention. However, tubular proteinuria of genetic origin typically does not improve with immunosuppression or antiproteinuric treatment. Recently, defects in CUBN were found to cause isolated proteinuria (mainly albuminuria) due to defective tubular albumin reuptake. Unlike most other genetically caused persistent albuminuria, CUBN C-terminal variants have a benign course without progression to chronic kidney disease according to the literature. Here, we present Korean cases with persistent proteinuria associated with C-terminal variants of CUBN. Methods: We identified Korean patients with CUBN variants among those with an identified genetic cause of proteinuria and evaluated their clinical features and clinical course. We also reviewed the literature on CUBN-associated isolated proteinuria published to date and compared it with Korean patients. Results: All patients presented with incidentally found, asymptomatic isolated proteinuria at a median age of 5 years. The proteinuria was in the subnephrotic range and did not significantly change over time, regardless of renin- angiotensin system inhibition. Initial physical examination, laboratory findings, and kidney biopsy results, when available, were unremarkable other than significant proteinuria. All patients maintained kidney function throughout the follow-up duration. All patients had at least one splicing mutation, and most of the variants were located C-terminal side of the gene. Conclusion: We report Korean experience of CUBN-related benign proteinuria, that aligns with previous reports, indicating that this condition should be considered in cases with incidentally found asymptomatic isolated proteinuria, especially in young children.