Autosomal dominant polycystic kidney disease (ADPKD):

ADPKD is an inherited disorder affecting 1 in 1,000 people and responsible for 10 % of cases of the end-stage renal disease (ESRD) [2]. The disease is caused by mutations in the PKD1 (85 % of cases) or PKD2 gene (15 % of cases). The precise processes leading to cyst formation and loss of renal function remain incompletely understood. Early diagnosis would be of benefit for efficient planning of therapy. Kistler [9] and other colleagues published their results in 2009. Using capillary electrophoresis and mass spectrometry, they analyzed urinary samples from 17 ADPKD patients and compared with 86 samples from age- and sex-matched apparently healthy controls. After a series of selecting and eliminating procedures, 38 proteins were eventually identified as biomarkers, most of which were collagen fragments. This suggests that there is high turnover of extracellular matrix proteins. Uromodulin peptides, previously implicated in tubular injury, were also found in the urine specimens. A support vector machine (SVM)-based model was then created by combining these 38 biomarkers and including additional controls to enable high specificity. This model applied to an independent masked dataset of 24 cases and 35 healthy controls discriminated ADPKD from controls with 87.5 % sensitivity and 97.5 % specificity (AUC: 0.95). Moreover, the model remained with a high sensitivity and specificity when additionally tested in normal controls, patients with different chronic renal diseases, with bladder cancer, with renal cell cancer and elderly group (aged >60).