Are birth defects in amish caused by a mutation or a chromosonal abnormality?

Both: Birth defects occur in every group of human beings on this earth. Often the cause is genetic, including chromosome rearrangements and mutations in single genes. Babies born to amish mennonite parents are no different. But in close-knit communities - amish, bedouin, roma, etc - parents are more likely to both carry the same mutation and bear a child with a genetic disease with # birth defects.