There are thousands of rare genetic diseases and many genetic and nongenetic contributors to common genetic diseases. The evidence base that is currently available about the great majority of these conditions is limited to case studies and relatively small observational study sets derived from one or several institutions. Hence, the statistical power in any one study is usually quite limited. Further, in the absence of organized registries and data collection on particular patient groups, the information available is weak and the patient resources that are available are limited. It is only through organized and coordinated clinical investigation systems that a sufficient number of patients with these diseases can be accumulated to provide the statistical power needed to inform about clinical history of treated and untreated forms, provide the resources needed for clinical trials of new tests and treatments, provide a sufficiently powered evidence base for public health decision-making and other uses. The meeting in which these issues were raised resulted in a set of proposed principles and associated recommendations as to how best to achieve the vision of creating an extensive and comprehensive collaboration of professional and lay communities to enable translational research to improve clinical care and therapies for persons with rare genetic diseases. ©2008The American College of Medical Genetics.