This application requests funding for the 2005 Gordon Research Conference on CAG Triplet Repeat Disorders to be held at Mount Holyoke College, South Hadley, Massachusetts from July 24-29, 2005. This will be the third Gordon Research Conference on CAG repeat disorders, the first was held in 2001 at Mount Holyoke College and the second was held in II Ciocco, Barga, Italy in May 2003. During the last decade, the mutation that causes a major group of inherited neurological disorders was found to be a CAG triplet repeat expansion. So far, this group of diseases includes Huntington's disease, the spinocerebellar ataxias 1, 2, 3, 6, 7 and 17, spinal and bulbar muscular atrophy and dentatorubral pallidoluysian atrophy. In each case, the CAG repeat lies within the coding region of the gene and results in an abnormally long polyglutamine tract in the mutant protein. Similarities in the underlying genetics and neuropathology suggest that the mechanisms of pathogenesis share common features. However, these diseases result in different anatomical distributions of the selective loss of neurons in the brain and spinal cord, and therefore the factors that distinguish them also need to be unraveled. Since the identification of the genetic defects, significant insights have been gained into the pathogenesis of these diseases. The field has progressed to the extent that the development of rational therapeutics is not only on the horizon but occurring already. In order to increase the pace of the basic research, and at the same time set in place the contacts and clinical resources necessary to move the basic science into the clinic, a multidisciplinary research effort is required. It is essential that collaborative projects between scientists from diverse specialties ranging from organic chemistry, fruit fly genetics to clinical neurology can be established. This conference on CAG triplet repeat disorders will gather together young investigators and established senior scientists to deliver provoking lectures on the cutting-edge of science. In keeping with the Gordon Research Conference format, there will be generous time allocated for both structured discussions led by peers and for informal discussions and social interactions to facilitate collaborations. Strong emphasis is placed on training and mentoring of young scientists, and time will be devoted to career issues. All participants will be required to present posters. Priority will be given to women, minorities, and persons with disabilities when selecting participants. ? ?