Involuntary voiding during sleep, nocturnal enuresis (NE), affects 7-10 % of all 7-year-olds, and 0.5-2 % of young adults. Night-time polyuria is one of the main pathogenic mechanisms. Today, the only method to diagnose nocturnal polyuria is home recordings involving diaper weight and registrations of first morning voids, which is very time-consuming. By using mass spectrometry (proteomics) on nocturnal urine samples from children with NE, the investigators aim to identify protein markers in relation to nocturnal polyuria. The perspective is to simplify an important part of the clinical characterization of NE patients.~This hypothesis-generating pilot project will be performed on 20 boys with NE. The children will have to collect:~Urine at bedtime on a wet and a dry night.~Urine during a wet night through a collecting device (non-invasive).~First morning voided volume following both a wet and a dry night.~Together with the analysis of a broad palette of peptides and proteins in the urine, there will be performed targeted analysis of arginine vasopressin (AVP), co-peptin and aquaporins, due to our knowledge about AVP and aquaporin roles as key regulators of the water balance in the body. Endpoints are any biomarkers in urine found to be associated with nocturnal polyuria. The proteomics methodologies are available at the proteomics core facility of Research Unit for Molecular Medicine, Dept. of Clinical Medicine, Aarhus University Hospital.~Based on the analytical uncertainty of the protein analysis methods, 20 samples are sufficient for detecting down to two-fold alterations in protein levels (p<0.05). By using state of the art mass spectrometry, the difference in any protein level between 1) the total urine amount on a wet and a dry night, and 2) first morning voided volume on a wet and a dry night, will be evaluated. Student's t-test with significance level at p<0.05 will be used.The amount of proteins in each urine sample will be correlated to the total amount of proteins in the respective sample.
The aim of the study is to identify protein markers in relation to the enuresis related nocturnal polyuria by using mass spectrometry (proteomics) on nocturnal urine samples. A biomarker for nocturnal polyuria would simplify an important part of the clinical characterization of enuresis patients.