The complex disease network. Network representation of the information available in complex diseases. The top layer represents patient information and links between patients reflect associations between patients such as family relationships, sexual contact, ethical background or geographical proximity. The lower layer contains information about factors underlying the complex phenotype as quantified in genetic studies, molecular profiling experiments, clinical data etc. There is a strong dependency structure between the two layers that connect individual patients to abnormalities in the lower layer. The network concept thus allows the representation of available information in a patient specific manner.