Coupling genomics and human genetics to delineate basic mechanisms of development

Special issues raised by evolving areas of clinical research

Each study presents its own set of ethical considerations. Certain kinds of ethical issues are inherent in particular areas of clinical research, regardless of specific ethical questions associated with a specific study. In this chapter, some of the most common special areas of clinical research are presented, highlighting the ethical issues most frequently associated with each.

Mouse models for gonadotropins: a 15-year saga

Pituitary gonadotropins FSH and LH are heterodimeric glycoproteins consisting of a common alpha and a hormone-specific beta subunit that are non-covalently linked. Both these hormones bind G-protein coupled receptors and regulate multiple processes in the gonads. Advances in the past two decades in manipulating the mouse genome by random and site-specific mutagenesis have been invaluable to our understanding of the biology of gonadotropins. Using these transgenic and gene targeting approaches, both gain-of-function transgenic as well as knockout mice lacking the hormone-specific gonadotropin subunits, and hence functional dimeric hormones were generated. Furthermore, knockout mice lacking regulators of gonadotropin production have also been characterized. These mice are useful to delineate the distinct in vivo biological roles of FSH and LH, and provide valuable genetic tools to study the signaling mechanisms within the gonads. Here, I will discuss our work on different ways to manipulate gonadotropin ligand function in the mouse.

Applying advances in neurogenetics to medical practice

The investigation of rare neurogenetic diseases is an example of how a translational science approach may lead to the delineation of complex genetic and biochemical pathways. Thisprocess comprises several intellectual stages. The first step involves the astute identification and clinical description of the unique phenotype, which may lead to obvious pathways or may reveal novel or unexpected mechanisms. As similar patients are identified, the establishment of databases detailing the clinical phenotype may serve to provide clues as to the genetic and biochemical characterization, and identification of the genetic mutation based on patient samples and animal or cellular models. Lastly, attempts to develop and apply therapies based on what has been learned about the biochemical and molecular bases of the disease enables intervention on the individual patient level. Several stages of discovery may overlap or be investigated simultaneously. As examples, this review discusses how this process of investigation has enabled progress in the delineation of several genetic and neurogenetic disorders, including Progeria syndrome, neurodegenerative diseases, muscular dystrophy, Rett syndrome and neurotransmitter disorders. This review attempts to summarize the transition from the bedside-to-bench-to-bedside as a model of bringing such discoveries into the clinical arena, and in doing so addresses the issues that may enhance, or complicate, such a path of discovery, as well as the impact such advances in genetics and genomics may have on the practice of clinical medicine and the role of the physician.