The Region 4 Genetics Collaborative has brought together metabolic clinicians and follow-up specialists from state departments of health in the region (Illinois, Indiana, Kentucky, Michigan, Minnesota, Ohio, and Wisconsin) in a workgroup to create a dynamic registry, the Inborn Errors of Metabolism Information System, to facilitate gathering information about long-term follow-up for individuals identified by newborn blood spot screening. With the concept that by developing a core series of agreed-on data elements and general treatment strategies, differences in treatment plans could yield evidence about optimal treatment choices, data elements for initial intake, and interval follow-up were selected based on a paradigm condition, medium-chain acyl-CoA dehydrogenase deficiency. Demographic elements that will be used as a common data set for all conditions were identified along with condition-specific elements and general information to be obtained at intervals. Subjects were enrolled after obtaining prospective informed consent; data entry began in January 2007. Additional conditions have had data sets defined and data entry initiated; 21 disorders as of July 2009. Web-based data entry has been employed using DocSite® as the platform for data entry. With continued collaboration among members of the workgroup, we hope to extend the intellectual questions that can be explored using this data, expand the spectrum of the registry and number of patients engaged, and integrate the registry into additional domains.