Most complex genetic disorders (such as schizophrenia, diabetes, hypertension and cancers) have a heterogeneous background. Multiple genetic risk variants have been proposed for these disorders. In the coming years, even more data are to be expected, e.g., from next-generation sequencing studies. The main challenge in understanding the etiology of complex disorders is to integrate the available genetic data into landscapes of interacting proteins that are involved in these disorders. Only in this way, we will be able to identify signaling cascades of interacting proteins that are involved in complex disorders and make genetic data amenable to use in the clinic.