VDR and inflammatory bowel disease: Vitamin D receptor (VDR) represents a strong positional candidate susceptibility gene for inflammatory bowel disease (IBD) [27] and is part of the training set (see Table S2); it is highly interconnected in the network associated with disease and also highly interconnected with hubs as a first neighbour (see Table 2); in addition, it is present in  over-represented and topologically segregated functional categories.