Genetics of Birth Defects: neuroendocrine, auditory, and skeletal development. We use two main approaches in our birth defects research - sequencing patient DNA to identify novel disease genes and use of cell culture and animal models, especially the mouse, to understand the mechanism and pathophysiology of disease. Genetically engineered mice that model human disease are also valuable for testing therapeutic interventions. We are particularly interested in the genetic control of differentiation and cell proliferation that pertains to stem cells, progenitors and specialized cells. We study transcriptional regulation, cell signaling, and the interaction of these.