Background Autosomal dominant polycystic kidney disease (ADPKD) is the most common monogenic cause of renal failure. For several decades, ADPKD was regarded as an adult-onset disease. In the past decade, it has become more widely appreciated that the disease course begins in childhood. However, evidence-based guidelines on how to manage and approach children diagnosed with or at risk of ADPKD are lacking. Also, scoring systems to stratify patients into risk categories have been established only for adults. Overall, there are insufficient data on the clinical course during childhood. We therefore initiated the global ADPedKD project to establish a large international pediatric ADPKD cohort for deep characterization. Methods Global ADPedKD is an international multicenter observational study focusing on childhood-diagnosed ADPKD. This collaborative project is based on interoperable Web-based databases, comprising 7 regional and independent but uniformly organized chapters, namely Africa, Asia, Australia, Europe, North America, South America, and the United Kingdom. In the database, a detailed basic data questionnaire, including genetics, is used in combination with data entry from follow-up visits, to provide both retrospective and prospective longitudinal data on clinical, radiologic, and laboratory findings, as well as therapeutic interventions. Discussion The global ADPedKD initiative aims to characterize in detail the most extensive international pediatric ADPKD cohort reported to date, providing evidence for the development of unified diagnostic, follow-up, and treatment recommendations regarding modifiable disease factors. Moreover, this registry will serve as a platform for the development of clinical and/or biochemical markers predicting the risk of early and progressive disease.

Circadian rhythm of water and solute excretion in nocturnal enuresis HYPOTHESIS: Several circadian rhythms of the kidney play a role in the pathogenesis of enuresis DESIGN & OUTCOMES:

Expert consensus papers recommend differentiating enuresis using questionnaires and voiding diaries into non- (NMNE) and monosymptomatic enuresis (MNE) is crucial at intake to decide the most appropriate workout and treatment. This national, Belgian, prospective study investigates the correlation, consistency, and added value of the two methods, the new against the old International Children’s Continence Society (ICCS) definitions, and documents the prevalence of the two enuresis subtypes in our population. Ninety treatment-naïve enuretic children were evaluated with the questionnaire, and the voiding diary and the two clinical management tools were compared. Almost 30% of the children had a different diagnosis with each method, and we observed inconsistencies between them in registering Lower Tract Symptoms (κ = –0.057–0.432 depending on the symptom). Both methods had a high correlation in identifying MNE (rs = 0.612, p = 0.001) but not for NMNE (rs = 0.127, p = 0.248). According to the latest ICCS definitions, the incidence of MNE was significantly lower (7 vs. 48%) with the old standardization.ConclusionThe voiding diary and the questionnaire, as recommended by the ICCS at the screening of treatment-naïve enuretic patients, are considerably inconsistent and have significantly different sensitivities in identifying LUTS and thus differentiating MNE from NMNE. However, the high incidence of LUTS and very low prevalence of MNE suggest that differentiating MNE from NMNE to the maximum might not always correlate with different therapy responses.