Growth hormone (GH) exerts multiple effects on different organs including the kidneys, either directly or via its main mediator, insulin-like-growth factor-1 (IGF-1). The GH/IGF1 system plays a key role in normal kidney development, glomerular hemodynamic regulation, as well as tubular water, sodium, phosphate, and calcium handling. Transgenic animal models demonstrated that GH excess (and not IGF1) may lead to hyperfiltration, albuminuria, and glomerulosclerosis. GH and IGF-1 play a significant role in the early development of diabetic nephropathy, as well as in compensatory kidney hypertrophy after unilateral nephrectomy. Chronic kidney disease (CKD) and its complications in children are associated with alterations in the GH/IGF1 axis, including growth retardation, related to a GH-resistant state, attributed to impaired kidney postreceptor GH-signaling and chronic inflammation. This may explain the safety of prolonged rhGH-treatment of short stature in CKD.

Purpose: Hypercalcemia with low parathyroid hormone (PTH) level, hypercalciuria, nephrocalcinosis, or nephrolithiasis, was recently reported as caused by mutations in CYP24A1 and SLC34A genes. These encode for vitamin D-24A-hydroxylase and for the renal phosphate transporters NaPiIIa and NaPiIIc, respectively. We aimed to describe the clinical course of these monogenic disorders in patients with and without found mutations during long-term follow-up.Methods: Ten patients with hypercalcemia, hypercalciuria, elevated 1,25-(OH)₂D levels and suppressed PTH were followed in our center during 1998–2019. Relevant laboratory and imaging data and results of genetic evaluation were retrieved from medical files.Results: The median age at presentation was 9.5 months (range 1 month−11 years), six were males, and the median follow-up time was 3.8 (1.1–14) years. Mutations in CYP24A1 and SLC34A3 were identified in three and one patients, respectively. Five patients presented with nephrocalcinosis, three with nephrolithiasis, and two had normal renal ultrasound. High blood calcium and 1,25-(OH)₂D levels at presentation decreased during follow-up [11.1 ± 1 vs. 9.9 ± 0.5 mg/dl (p = 0.012), and 307 ± 130 vs. 209 ± 65 pmol/l (p = 0.03), respectively]; this paralleled an increase in suppressed PTH levels (5.8 ± 0.9 vs. 11.8 ± 7.3 pg/ml, p = 0.2). Substantial improvements in hypercalciuria and renal sonography findings were not observed. Two patients had impaired renal function (eGFR 84–88 ml/min/1/73 m²) at the last follow up. Interventions included appropriate diet, citrate supplementation, and thiazides.Conclusion: Despite improvement in hypercalcemia and 1,25-(OH)₂D levels, not all the patients showed improvements in hypercalciuria and nephrocalcinosis. Deterioration of renal function was also observed. Long-term follow up and intervention to prevent nephrocalcinosis and nephrolithiasis are recommended in these children.

Aim: To determine the duration of relapsing childhood idiopathic nephrotic syndrome (INS).Methods: In this population‐based study, we retrospectively analysed the computerised database of Israel's largest health maintenance organisation. Children (age 2–10 years) with a new INS diagnosis and a corticosteroid (CS) prescription between 2000 and 2010 were included. NS category was determined, according to CS and/or steroid‐sparing agents (SSA) purchases.Results: Out of 1 669 977 eligible children, 608 fulfilled inclusion criteria. Patients in the fourth quartile of purchases (n = 132) had an older age at last relapse (17.9 ± 6.3 vs. 11.3 ± 5.9 years, p < 0.001) and more SSA use (78.8% vs. 20%, p < 0.001) compared to the remaining three quartiles. A single episode occurred in 84 patients. Of the remaining 524 patients (males 66%, diagnosis age: 4.8 ± 2.2 years, SSA prescribed: 35%) who were followed for 15.5 ± 5.1 years, 113 (21.6%) had a continuing disease at an age of 19.3 ± 6.3 years. The leftover 411 entered long‐lasting treatment‐free remission at age 11.2 ± 5.7 years.Conclusion: In this multicentre study, we identified INS disease course by medication delivery. NS long‐standing remission occurs at age 11.2 ± 5.7 years in most cases. However, the disease continues into adulthood in a fifth of the relapsing patients, implicating the need for proper transition to adult care.

Cystic fibrosis (CF) is a multiorgan disease, caused by autosomal recessive (AR) mutations in the cystic fibrosis transmembrane regulator (CFTR) acting primarily as a chloride channel. CF is most commonly diagnosed in Caucasian populations. Common clinical presentations in pediatric patients include chronic cough, respiratory tract infections such as pneumonia, digestive symptoms, and stunted growth, and malnutrition due to gastrointestinal malabsorption and pancreatic insufficiency. Excessive sweat sodium chloride losses due to dysfunctional sweat glands in CFTR result in volume contraction and secondary hyperaldosteronism leading to renal potassium losses and metabolic alkalosis. Hypokalemic hypochloremic metabolic alkalosis is a known but uncommon presenting sign of the disease, documented as pseudo Bartter syndrome. Common mutations in the CFTR gene are now included in prenatal genetic screening programs. We describe the case of an infant of African descent with normal prenatal screening who presented with severe hypokalemic hypochloremic metabolic alkalosis and was diagnosed with CF with further genetic confirmation of the diagnosis.

Immunoglobulin A vasculitis (IgAV) is a small vessels immunoglobulin A (IgA)-mediated vasculitis with multiorgan involvement. Kidney involvement (IgAV nephropathy [IgAVN]) occurs in 30%–50% of patients and usually appears at or within 6-month of initial presentation. The converse, with nephritis preceding other manifestations, is rare. We describe a 5.5-year-old boy, who presented with recurrent hematuria syndrome during upper respiratory tract infections. This preceded, by several months, the appearance of a palpable purpuric rash. Skin biopsy confirmed leukocytoclastic vasculitis with predominant IgA deposition. Serum level of complement was normal. Serum creatinine was elevated mildly and transiently during each gross hematuria event. Nephrotic range proteinuria resolved after macrohematuria resolution without residual proteinuria or decreased kidney function 12 months after initial presentation. IgAVN may manifest with isolated recurrent glomerulonephritis preceding purpura. This case emphasizes that children with normocomplementemic recurrent hematuria syndrome should be regularly examined for the possible later appearance of other signs of IgAV.