The Amish Protective Variant Study, based at Case Western Reserve University and the University of Miami (Cummings et al. 2012; D’Aoust et al. 2015), is being conducted in the Indiana and Ohio Old Order Amish (OOA) population. The OOA, an isolated founder population originating from emigration of German and Swiss Anabaptists to the U.S. in the 1700’s and 1800’s has been examined in multiple genetic studies of complex diseases including AD, age-related macular degeneration, and successful aging. With fewer than 1,000 founders and self-imposed cultural and religious isolation, the introduction of genetic variation among the OOA has been significantly restricted. Anecdotally, their agrarian lifestyle and firm behavioral norms likely have reduced variation in environmental exposures. Further, the OOA are an excellent population for genetic studies in that they have large and stable pedigrees and low variability in lifestyle factors.

Individuals included in this study have been recruited over the past 20 years for multiple studies of AD or dementia, age-related macular degeneration, and successful aging. For all these studies, the primary criteria for enrollment included being age 50 or older (AMD), age 60 or older (AD), or age 80 or older (successful aging), being part of the Amish community, and being of Amish descent. Recruitment primarily included community-based home visits. Participants were recruited from Amish families living in Holmes County, Ohio and Elkhart, LaGrange, and Adams Counties, Indiana.

Nuclear family pedigrees are provided for convenience. However, as a founder population, these Amish individuals have, on average, a genetic relationship between the equivalent of second and third cousins. Thus additional, more complex relationships exist across the nuclear pedigrees.