Network medicine: linking disorders.

The molecular events underlying many human hereditary disorders remain to be discovered despite the significant advances made in molecular biology and genetics in the past years. Given the complexity of cellular systems and the interplay between different functional modules, it is becoming increasingly evident that profound insights into human disease cannot be derived by analyzing single genetic defects. The generation of different types of disease interaction networks has recently emerged as a unifying approach that holds the promise of shedding some light on common pathological mechanisms by placing the single disorders into a larger context. In this review, I summarize the rationale behind these disease networks and different ways of constructing them. Finally, I highlight some of the first results that have been obtained by systematically analyzing the intertwined relationships between human disorders because they suggest that the current disease classification does not always sufficiently reflect biologically and medically relevant disease relationships.