Families of Amish/Mennonite background which include at least one individual with a clinical phenotype and a pedigree suggestive of genetic disease will be considered for the undiagnosed disease portion of the study. Initial outreach will be to Plain Communities in western Pennsylvania, but all Pain Community members are eligible as long as they have been evaluated by a local clinical geneticist. Any individual (and their family members) from the Plain Community is eligible for the population based studies of founder effects and genetic drift.