Virtually all diseases have a genetic component. The goal of the Program in Disease Gene Discovery (PDGD) is to uncover the role of genetic variation in specific human traits. The characterization of genetic and environmental influences in human disorders delivers new knowledge of human biology that can be translated into health care modifications and improvements for patients and their families. The PDGD integrates ascertainment of participants and collection of biological samples, clinical data and risk factor data with molecular characterization and statistical analysis. The CHGR has internationally recognized research excellence in neurogenetic and neurodevelopmental disorders, ophthalmologic disorders, psychiatric disorders, obstetrical and pediatric disorders, lung disorders, cardiovascular disorders, cancer and infectious diseases. Critical to our success is the recognition of both gene x gene and gene x environment interactions. The PDGD combines the expertise of clinicians, genetic epidemiologists and molecular geneticists at Vanderbilt and collaboratively throughout the world.