"Maple Syrup Urine Syndrome"

Clicking around out of curiosity about the Amish, in light of the events of last week, I found quite a lot of medical literature about them. Apparently they're so inbred, pinched in such a genetic bottleneck, that they are prone to a lot of rare diseases and deformities. Sad.

But the price of a simple life can be high. The Amish in Lancaster County are descendants of about 200 Swiss Anabaptists who emigrated in the mid- 1700s (other groups of Amish settled elsewhere in Pennsylvania and other states). The Amish church forbids marriage outside the order and few outsiders have joined, so the community has been essentially a closed genetic population for more than 12 generations. Thus, intermarriage has brought to the fore certain genetic mutations that were present in the initial genetic pool (as they are in any population), making the Amish host to several inherited disorders. These mostly stem from recessive traits and include forms of dwarfism and mental retardation, as well as the diseases that interest pediatrician Holmes Morton--a collection of treatable metabolic disorders including Bartter's. The Amish have twice the risk for certain diseases than people in the general population. The Mennonites have also passed down particular genetic diseases, including maple syrup urine disease, so named because patients' urine and earwax contain a metabolite that smells like maple syrup. The disease can cause irreversible brain damage in days; if untreated, it claims the lives of infants within the first week of life.

"I juggle about 50 different disorders like this," explains Morton, an instructor in pediatrics at Hopkins, as he bounces through the Lancaster countryside in his Jeep following his visit to the Stolzfus family. "Most of them are poorly defined. It really is experimental medicine to figure out what to do. It's all a learning experience."