? DATABASE AND BIOREPOSITORY CORE ABSTRACT Here we describe the Database and Biorepository Core of the National Center for the Identification and Study of Individuals with Atypical Diabetes Mellitus. The purpose of the Core is to develop a community resource to advance research in this area through the collection and dissemination of data and biorepository samples, with an ongoing living biobank, for access by the diabetes research community. The central hypothesis of the entire center is that the identification and study of new cases of rare/atypical forms of diabetes will yield greater insights into the etiology and genetic heterogeneity of type 2 diabetes mellitus (T2DM). This Core will support the goals of the Center by: 1) Creating and managing a database for participants with rare/atypical diabetes; 2) Facilitating a national network of collaborators to help identify and initially phenotype the individuals in pedigrees identified; 3) Establishing a unique living biobank and biospecimen repository for rare/atypical forms of diabetes for use by the broader research community in future analyses; and 4) Establishing a platform for the greater scientific community to request access to view phenotypic and genotypic data, as well as available samples from the living biobank. The Database and Biorepository Core will facilitate subsequent studies to characterize rare/atypical subtypes identified by the center. Future studies using this data may help reveal novel mechanistic pathways involved in the pathogenesis of diabetes. Identification of these novel genes and pathways will point to novel strategies for the diagnosis, treatment, and prevention of T2DM.!