In the human disease network each node corresponds to a disease and its size indicates the number of genes, that are known to be associated with that disease. Diseases/nodes are connected to one another if they have associated genes in common.
Diseasome is a research project for exploring relationships of diseases/disorders based on the study The Human Disease Network, Goh K-I, Cusick ME, Valle D, Childs B, Vidal M, Barabási A-L (2007), Proc Natl Acad Sci USA 104:8685-8690.
You can zoom in and out the graph with the mouse wheel. You can move the graph by clicking and holding the left mouse button and moving the mouse. When you zoom into the graph more disease names will be shown.
To highlight diseases or genes and their connections type the name in the top menu's search form.