Clinic For Special Children - Amish and Genetics

Amish and Genetics

The vast majority of the nearly 200,000 Amish in America derive from about 200 families who moved from the lower Rhine valley, the German Palatinate and Alsace in the 18th century, though there have been some converts from the outside "English" world. The Amish do not allow marriage outside of the faith, therefore their gene pool is more shallow than that of the average person. Some Amish are afflicted by heritable genetic disorders, including dwarfism (Ellis-van Creveld syndrome), and are also distinguished by the highest incidence of twins in a known human population, various metabolic disorders, and unusual distribution of blood types. Since almost all of the current Amish descend primarily from about 200 founders in the 18th century, some genetic disorders from a degree of inbreeding do exist in more isolated districts. However, Amish do not represent a single closed community, but rather a collection of different demes or genetically-closed communities. Some of these disorders are quite rare, or even unique, and they are serious enough that they increase the mortality rate among Amish children. The majority of the Amish accept these as "Gottes Wille" (God's will); they reject any use of genetic tests prior to marriage to prevent these disorders as well as genetic testing of unborn children that would discover any genetic disorder.

There is an increasing consciousness among the Amish of the advantages of exogamy. A common bloodline in one community will often be absent in another, and genetic disorders can be avoided by choosing spouses from unrelated communities. For example, the founding families of the Lancaster County Amish are unrelated to the founders of the Perth County Amish community in Canada.

Treating genetic problems is the mission of the Clinic which has developed effective treatments for such problems as maple syrup urine disease, a disease which previously was fatal. The clinic has been enthusiastically embraced by most Amish, and has largely ended a situation in which some parents felt it necessary to leave the community to care properly for their children, an action which normally might result in being shunned.