“The Amish are at an increased risk for a number of genetic disorders but they probably have protection against many types of cancer both through their lifestyle – there is very little tobacco or alcohol use and limited sexual partners – and through genes that may reduce their susceptibility to cancer”
One form of dwarfism, Ellis-van Creveld syndrome, involves not only short stature but polydactyly (extra fingers or toes), abnormalities of the nails and teeth, and, in about half of individuals, a hole between the two upper chambers of the heart. The syndrome is common in the Amish because of the "founder effect."