PROJECT SUMMARY Acute pancreatitis (AP) is increasingly recognized in children, with an incidence approaching that of adults. Most children with pancreatitis have a single, mild, acute episode that resolves without complications. However, a subset of children with AP develops recurrent episodes (defined as acute recurrent pancreatitis or ARP) and some progress to chronic pancreatitis (CP). Pediatric ARP and CP significantly impact quality of life and carry high healthcare costs. Few studies have been performed to characterize the natural history pediatric ARP and CP, to identify its risk factors and to determine predictors of disease course. As INSPPIRE (INternational Study Group of Pediatric Pancreatitis: In search for a cuRE), the first multicenter, multidisciplinary collaboration in pediatric pancreatitis, we determined that children with ARP harbor multiple genetic risk variants and rapidly transition to CP, exocrine pancreatic insufficiency (EPI) and diabetes mellitus (DM). The risk factors that predispose children to early onset pancreatitis, rapid progression to CP and premature loss of exocrine and endocrine function are not well-known. The objective of this application is to delineate the natural history of pediatric CP through careful prospective analysis of INSPPIRE-2 cohort, to define the impact of genetic modifiers on disease course and to determine the mechanisms involved in pancreatogenic diabetes mellitus (T3cDM). The overall hypothesis is that genetic factors predispose children to early onset CP, EPI, and DM. Our specific aims are: 1) Characterize pediatric CP, determine predictors of disease onset and progression; 2) Determine the impact of genetic variants on disease onset and progression; 3) Identify mechanisms underlying disturbed glucose regulation in pediatric ARP and CP. This project will provide insight into the pathophysiology of pediatric pancreatitis, investigate the impact of genetic variants on disease course and explore the mechanisms of early islet cell dysfunction in pediatric ARP and CP. Our long-term goal is to develop diagnostic modalities, prognostic factors and innovative treatment approaches for pediatric ARP and CP.