Matko Marlais

Anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (AAGN) is a rare phenomenon in children and is associated with a significant risk of kidney failure. Over the last decade, there have been updates to clinical guidelines for the immunosuppressive management of this condition, but these continue to be based predominantly on clinical trial data in adults. Recent clinical trials have resulted in increasing use of rituximab for both maintenance and induction treatment, with renewed focus on the role of plasma exchange as part of induction treatment which remains controversial. Newer complement-targeting agents may provide an effective but more targeted and less toxic treatment strategy. This review focuses on immunosuppressive strategies for induction and maintenance treatment, considering recommendations from recent clinical guidelines and how these may be adapted for children and young people with AAGN. Graphical Abstract A higher resolution version of the Graphical Abstract is available as Supplementary information.

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder which can have manifestations in the kidneys, along with other organ systems. Children with TSC may develop kidney lesions at any point during childhood, and typically these are angiomyolipomata (AML) and/or kidney cysts. Children may also have hypertension associated with TSC-associated kidney disease, and rarely reduced kidney function. New guidelines for the management of TSC-associated kidney disease in children and adults were published in 2024. This educational review summarises the relevant clinical aspects of these guidelines for paediatric nephrologists through a series of four clinical cases. These cases cover management of hypertension, frequency of follow-up and frequency of kidney imaging. Difficult clinical scenarios are reviewed, such as the management of TSC2-PKD1 contiguous gene syndrome and the management of large AMLs in children with TSC. Graphical abstract

Background: Tuberous sclerosis (TSC)–associated kidney disease is a leading cause of mortality in adults with TSC. This study aimed to understand TSC features in children, particularly kidney involvement, to inform clinical care for this specific group. Methods: This retrospective cohort study included all paediatric (< 19 years) TSC cases at a large tertiary paediatric nephrology centre. Relevant data were collected from patients’ records, statistical analyses were performed to identify associations between variables, survival probabilities were estimated with Kaplan‒Meier curves, and log-rank tests were conducted to assess survival differences among genetic mutations. Results: A total of 182 children with TSC were included. Among the 145 children with available kidney imaging data, 78.6% (114/145) exhibited kidney lesions. Angiomyolipomas (AMLs) were significantly more prevalent in the TSC2 mutation group (p = 0.018). Children with TSC2 mutations generally had poorer lesion-free survival than those with TSC1 mutations, but this difference was only significant for AMLs (p = 0.030). The change in size of largest AMLs increased with age and doubled in children above 9 years; a similar pattern was observed when stratified by genetic mutation. In contrast, kidney cysts exhibited two peaks: one in children under 5 years (2.31 mm/year) and the second in children between 15–19 years (2.82 mm/year). Chronic kidney disease was observed in 12.3% (10/81) of children, and high-risk AMLs above 3 cm were observed in 9% (13/145). Conclusions: While TSC kidney disease emerges later in the disease course than neurological features, our findings emphasise the importance of kidney surveillance during childhood, including routine kidney imaging, kidney function, and blood pressure monitoring. Graphical

The purpose of this study is to determine the predictive factors of tuberous sclerosis complex (TSC)-associated kidney disease and its progression in children. Retrospective review of children with TSC in a tertiary children’s hospital was performed. Relevant data were extracted, and Cox proportional hazards regression was used to establish predictors of kidney lesions. Logistic regression was conducted to identify factors predicting chronic kidney disease (CKD) and high-risk angiomyolipomas (above 3 cm). Kidney imaging data were available in 145 children with TSC; of these, 79% (114/145) had abnormal findings. The only significant predictive factor for cyst development was being female (HR = 0.503, 95% CI 0.264–0.956). Being female (HR = 0.505, 95% CI 0.272–0.937) and underweight (HR = 0.092, 95% CI 0.011–0.800) both lowers the risk of having angiomyolipomas, but TSC2 mutations (HR = 2.568, 95% CI 1.101–5.989) and being obese (HR = 2.555, 95%CI 1.243–5.255) increases risks. Ten (12%) of 81 children with kidney function tested demonstrate CKD stages II–V, and only angiomyolipomas above 3 cm predict CKD. Additionally, 13/145 (9%) children had high-risk angiomyolipomas, whereby current age (adjusted odds ratio (aOR) 1.015, 95% CI 1.004–1.026) and being overweight/obese (aOR 7.129, 95% CI 1.940–26.202) were significantly associated with angiomyolipomas above 3 cm.Conclusions: While gender and genotype are known predictors, this study includes the novel finding of nutritional status as a predictor of TSC-associated kidney disease. This study sheds light on a possible complex interplay of hormonal influences, obesity, and kidney angiomyolipomas growth, and further investigations focusing on the impact of nutritional status on TSC-associated kidney disease are warranted. What is Known:• Gender and genotype are well-studied predictive factors in TSC kidney disease. What is New:• Nutritional status may influence the development and the progression of kidney lesions in children with TSC and should not be overlooked. • Management guidelines of TSC-associated kidney disease can address nutritional aspects.

Congenital anomalies of the kidney and urinary tract are collectively one of the most commonly diagnosed antenatal conditions. Clinicians have several tools available to diagnose anomalies, including imaging, biomarkers, family history and genetic studies. In certain cases, antenatal interventions such as vesico-amniotic shunting may be considered to improve postnatal outcomes.Congenital kidney anomalies detected antenatally can vary in clinical significance from almost no impact postnatally to significant morbidity and perinatal mortality. Prognosis broadly depends on kidney size, structure and amount of amniotic fluid, alongside genetics and family history, and progression on subsequent scans. It is important to counsel parents appropriately using a parent-focused and personalised approach. The use of a multidisciplinary team should always be considered.

Introduction: Rickets is a bone disease caused by a defect in mineralization. When left untreated, it has lifelong Orthopaedic sequelae. Burosumab, an anti-fibroblast growth factor 23 monoclonal antibody, improves rickets severity, symptoms, and growth in children with X-linked hypophosphataemia (XLH) followed to 64 weeks in clinical trials. International dosing guidance recommends targeting normal serum phosphate concentration. However, some children may not achieve this despite maximal dosing. This study compares clinical outcomes in children with XLH on long-term burosumab treatment who achieved normal phosphate, vs those who did not. Methods: Single-centre retrospective review of a large paediatric cohort with XLH treated with burosumab. We evaluated growth and biochemical markers of bone health in those who did compared to those who did not achieve normal plasma phosphate concentration. Results: Fifty-five children with XLH with median age 11.7 [6.8–15.5] years were included. 27 (49%) had low plasma phosphate concentration, and 27 (49%) normal phosphate after a median burosumab treatment duration of 3.3 [IQR 2.6–3.7] years. 1 (2%) did not have a recent phosphate level recorded. No difference in growth was found between normal and abnormal phosphate groups (p = 0.9). A trend of superior growth in those with normal compared with abnormal alkaline phosphatase level was observed. Conclusion: Young children with XLH experience sustained growth on long-term burosumab treatment, albeit without normal plasma phosphate concentration in many. Consideration should be made to changing burosumab dosing recommendations to target the normalisation of alkaline phosphatase instead of plasma phosphate concentration.

This is an overview of the challenges associated with screening for asymptomatic intracranial aneurysms (ICA) in children with autosomal dominant polycystic kidney disease (ADPKD). ADPKD is the most common inherited kidney disease affecting 1 in 1,000 people. ICAs are an extra-kidney manifestation of ADPKD, and while the exact pathophysiology of how they develop is unknown, we know that they more commonly occur in the adult rather than paediatric population. ICAs can be found in up to 9–11.5% of adults with ADPKD, but ICA rupture remains a rare event in adults with an incidence of 0.04 per 100 patient years. ICA size is an important factor in determining the risk of aneurysm rupture and therefore affects the decision on intervention in asymptomatic adults. For some, unruptured aneurysms cause no clinical significance, but those that rupture can be associated with devastating morbidity and mortality. Therefore, if detected, the treatment for unruptured ICAs is usually endovascular coiling, alongside recognising the importance of preventative interventions such as hypertension management. There are, however, no current guidelines for either adult or paediatric patients with ADPKD supporting regular screening for asymptomatic ICAs, although there is a suggestion for individualised practice, for example, with those with a positive family history. The UK clinical guidelines for ADPKD in children make research recommendations due to a lack of published literature, which in itself indicates that ICA rupture is an extremely rare phenomenon in children.

Background The aim of this study was to investigate whether being on dialysis at the time of renal transplantation affected renal allograft survival in paediatric renal transplant recipients (pRTRs). Methods Retrospective study of UK Transplant Registry (National Health Service Blood and Transplant) data on all children (aged Results 2038 pRTRs were analysed: 607 (30%) were pre-emptively transplanted, 789 (39%) and 642 (32%) on peritoneal dialysis and haemodialysis, respectively, at the time of transplantation. Five-year renal allograft survival was significantly better in the pre-emptively transplanted group (90.6%) compared with those on peritoneal dialysis and haemodialysis (86.4% and 85.7%, respectively; p=0.02). After accounting for donor type, there was a significantly lower hazard of 5-year renal allograft failure in pre-emptively transplanted children (HR 0.742, p=0.05). Time spent on dialysis pre-transplant negatively correlated with renal allograft survival (p=0.002). There was no significant difference in 5-year renal allograft survival between children who were on dialysis for less than 6 months and children transplanted pre-emptively (87.5% vs 90.5%, p=0.25). Conclusions Pre-emptively transplanted children have improved 5-year renal allograft survival, compared with children on dialysis at the time of transplantation. Although increased time spent on dialysis correlated with poorer renal allograft survival, there was no evidence that short periods of dialysis pre-transplant affected renal allograft survival.