Chyloperitoneum in a toddler on peritoneal dialysis.

Chyloperitoneum is an uncommon diagnosis in peritoneal dialysis (PD) patients. While admitted for emesis and feeding intolerance, a 16-month-old male on PD developed milky-colored dialysate with increased triglycerides, indicating chyloperitoneum. In adult PD patients, chyloperitoneum can indicate potentially life-threatening pathologies including malignancies and liver or heart disease.

Hypercalcemia Secondary to Elevated PTHrP in an Infant Followed by Progression to Nephrotic Syndrome.

In infants, hypercalcemia from elevated parathyroid hormone-related protein (PTHrP) is rare, often signaling neoplasm or renal or urinary anomalies. We report an infant who presented with failure to thrive and hypercalcemia at 10 months old, with initial evaluation showing elevated PTHrP of unclear etiology with imaging negative for neoplasm and no structural anomalies of the kidneys or ureters on ultrasound. Within 6 months of presentation, the patient developed nephrotic syndrome and by 2 years had progressed to end-stage kidney disease, necessitating kidney transplantation.

An update on clinical presentation and responses to therapy of patients with hereditary hypophosphatemic rickets with hypercalciuria (HHRH).

Pathogenic variants in solute carrier family 34, member 3 (SLC34A3), the gene encoding the sodium-dependent phosphate cotransporter 2c (NPT2c), cause hereditary hypophosphatemic rickets with hypercalciuria (HHRH). Here, we report a pooled analysis of clinical and laboratory records of 304 individuals from 145 kindreds, including 20 previously unreported HHRH kindreds, in which two novel SLC34A3 pathogenic variants were identified. Compound heterozygous/homozygous carriers show above 90% penetrance for kidney and bone phenotypes.

A rare cause of posterior reversible encephalopathy syndrome: Acute lymphoblastic leukemia.

Key Clinical Message: The presentation of posterior reversible encephalopathy syndrome (PRES) as the initial presenting sign of acute lymphoblastic leukemia is unusual, as PRES is more often a complication of therapy. This case highlights the importance of maintaining a broad differential diagnosis for pediatric hypertension and its complications.

Abstract: A 6-year-old male presented with a seizure-like episode.

Genetic testing in children with nephrolithiasis and nephrocalcinosis.

Background: Diagnosing genetic kidney disease has become more accessible with low-cost, rapid genetic testing. The study objectives were to determine genetic testing diagnostic yield and examine predictors of genetic diagnosis in children with nephrolithiasis/nephrocalcinosis (NL/NC).

Methods: This retrospective multicenter cross-sectional study was conducted on children ≤ 21 years old with NL/NC from pediatric nephrology/urology centers that underwent the Invitae Nephrolithiasis Panel 1/1/2019-9/30/2021.

Age of Onset and Disease Course in Biopsy-Proven Minimal Change Disease: An Analysis From the Cure Glomerulonephropathy Network.

Rationale & Objective: Adolescent- and adult-onset minimal change disease (MCD) may have a clinical course distinct from childhood-onset disease. We characterized the course of children and adults with MCD in the Cure Glomerulonephropathy Network (CureGN) and assessed predictors of rituximab response.

Study Design: Prospective, multicenter, observational study.

Thrombotic Microangiopathy Due to Progressive Disseminated Histoplasmosis in a Child With Down Syndrome and Acute Lymphoblastic Leukemia.

Histoplasmosis, a common mycosis in the south-central United States, may be life threatening in immunocompromised patients. We describe a 4-year-old female with Down syndrome and acute lymphoblastic leukemia who developed hemolytic anemia, thrombocytopenia, and renal failure, consistent with thrombotic microangiopathy. Bone marrow biopsy revealed non-necrotizing granulomas with GMS staining demonstrating budding yeast.

Pioglitazone enhances proteinuria reduction in complicated pediatric nephrotic syndrome.

Background: Nephrotic syndrome (NS) is a common pediatric kidney disease, yet current treatments for complicated NS are only partially effective and have significant toxicity. There is no Food and Drug Administration (FDA)- or European Medicines Agency (EMA)-approved safe and effective treatment for NS. Thiazolidinediones (TZDs) have been shown to reduce proteinuria in both diabetic and non-diabetic kidney disease and in preclinical studies to directly protect podocytes from injury and reduce proteinuria.

ePHex: a phase 3, double-blind, placebo-controlled, randomized study to evaluate long-term efficacy and safety of Oxalobacter formigenes in patients with primary hyperoxaluria.

Background: Primary hyperoxalurias (PHs) are rare genetic diseases that increase the endogenous level of oxalate, a waste metabolite excreted predominantly by the kidneys and also the gut. Treatments aim to improve oxalate excretion, or reduce oxalate generation, to prevent kidney function deterioration. Oxalobacter formigenes is an oxalate metabolizing bacterium.

IgA-dominant infection-associated glomerulonephritis in the pediatric population.

Background: IgA-dominant infection-associated glomerulonephritis is well-documented in adults but has not been studied in depth in children. We assessed the incidence of pediatric IgA-dominant infection-associated glomerulonephritis and clinical and kidney biopsy findings.

Methods: Pediatric native kidney biopsies over a 10-year period with IgA dominance, strong C3, and findings indicative of infection-associated etiology were identified.

Eculizumab exposure in children and young adults: indications, practice patterns, and outcomes-a Pediatric Nephrology Research Consortium study.

Background: Eculizumab is approved for the treatment of atypical hemolytic uremic syndrome (aHUS). Its use off-label is frequently reported. The aim of this study was to describe the broader use and outcomes of a cohort of pediatric patients exposed to eculizumab.

Predicting Adverse Outcomes for Shiga Toxin-Producing Escherichia coli Infections in Emergency Departments.

Objective: To assess the performance of a hemolytic uremic syndrome (HUS) severity score among children with Shiga toxin-producing Escherichia coli (STEC) infections and HUS by stratifying them according to their risk of adverse events. The score has not been previously evaluated in a North American acute care setting.

Study Design: We reviewed medical records of children <18 years old infected with STEC and treated in 1 of 38 participating emergency departments in North America between 2011 and 2015.

Urinary apolipoprotein AI in children with kidney disease.

Background: Although high-density lipoprotein (HDL) modulates many cell types in the cardiovascular system, little is known about HDL in the kidney. We assessed urinary excretion of apolipoprotein AI (apoAI), the main protein in HDL.

Methods: We enrolled 228 children with various kidney disorders and 40 controls.

Predicting Hemolytic Uremic Syndrome and Renal Replacement Therapy in Shiga Toxin-producing Escherichia coli-infected Children.

Background: Shiga toxin-producing Escherichia coli (STEC) infections are leading causes of pediatric acute renal failure. Identifying hemolytic uremic syndrome (HUS) risk factors is needed to guide care.

Methods: We conducted a multicenter, historical cohort study to identify features associated with development of HUS (primary outcome) and need for renal replacement therapy (RRT) (secondary outcome) in STEC-infected children without HUS at initial presentation.

Genetic Testing for Steroid-Resistant-Nephrotic Syndrome in an Outbred Population.

Steroid-resistant nephrotic syndrome (SRNS) is a leading cause of end-stage kidney disease in children and young adults. Despite advances in genomic science that have led to the discovery of >50 monogenic causes of SRNS, there are no clear guidelines for genetic testing in clinical practice. Using high throughput sequencing, we evaluated 492 individuals from 181 families for mutations in 40 known SRNS genes.

Lack of IL7Rα expression in T cells is a hallmark of T-cell immunodeficiency in Schimke immuno-osseous dysplasia (SIOD).

Schimke immuno-osseous dysplasia (SIOD) is an autosomal recessive, fatal childhood disorder associated with skeletal dysplasia, renal dysfunction, and T-cell immunodeficiency. This disease is linked to biallelic loss-of-function mutations of the SMARCAL1 gene. Although recurrent infection, due to T-cell deficiency, is a leading cause of morbidity and mortality, the etiology of the T-cell immunodeficiency is unclear.

A novel splice site mutation in SMARCAL1 results in aberrant exon definition in a child with Schimke immunoosseous dysplasia.

Schimke Immunoosseous Dysplasia (SIOD) is a rare, autosomal recessive disorder of childhood characterized by spondyloepiphyseal dysplasia, focal segmental glomerulosclerosis and renal failure, T-cell immunodeficiency, and cancer in certain instances. Approximately half of patients with SIOD are reported to have biallelic mutations in SMARCAL1 (SWI/SNF-related matrix-associated actin-dependent regulator of chromatin, subfamily a-like 1), which encodes a DNA translocase that localizes to sites of DNA replication and repairs damaged replication forks. We present a novel mutation (NM_014140.

Dysfunctional high-density lipoproteins in children with chronic kidney disease.

Objectives: Our aim was to determine if chronic kidney disease (CKD) occurring in childhood impairs the normally vasoprotective functions of high-density lipoproteins (HDLs).

Materials And Methods: HDLs were isolated from children with end-stage renal disease on dialysis (ESRD), children with moderate CKD and controls with normal kidney function. Macrophage response to HDLs was studied as expression of inflammatory markers (MCP-1, TNF-α, IL-1β) and chemotaxis.

HLA-DQA1 and PLCG2 Are Candidate Risk Loci for Childhood-Onset Steroid-Sensitive Nephrotic Syndrome.

Steroid-sensitive nephrotic syndrome (SSNS) accounts for >80% of cases of nephrotic syndrome in childhood. However, the etiology and pathogenesis of SSNS remain obscure. Hypothesizing that coding variation may underlie SSNS risk, we conducted an exome array association study of SSNS.

Schimke Immunoosseous Dysplasia associated with undifferentiated carcinoma and a novel SMARCAL1 mutation in a child.

Schimke Immunoosseous Dysplasia (SIOD) is a rare, autosomal recessive disorder of childhood with classical features of spondyloepiphyseal dysplasia, renal failure, and T cell immunodeficiency. SIOD has been associated with several malignancies, including non-Hodgkin lymphoma and osteosarcoma. About half of SIOD patients have biallelic mutations in SMARCAL1 (SWI/SNF-related matrix-associated actin-dependent regulator of chromatin, subfamily a-like 1).