"When Dr. Morton told us that our daughter Barbie Ann had glutaric aciduria, John and I thought he had made a mistake," says Lydia Stoltzfoos, daughter-in-law of Jacob and Naomi. But Barbie Ann soon developed a fever, and Morton admitted her to Lancaster General. Stressed by infection, a child with glutaric aciduria does not metabolize certain amino acids normally. The resulting buildup of glutarate attacks the nervous system and damages the basal ganglia, a part of the brain that controls body movement. Once brain injury occurs, a child never recovers. "If it weren't for Dr. Morton and the clinic," Lydia says, "Barbie Ann would have ended up like many of Amos and Suzie Miller's children. Five of them died or are paralyzed because of this disease."

Over the years, Morton has traced each family's genetic heritage through 14 generations. He has determined a carrier frequency for the disorder among the Amish of about 1 in 10 people. Working with Dr. Richard Kelley, a pediatrician, Morton diagnosed glutaric aciduria in 16 other Amish children. The doctors' studies predicted that 50 more children born in the next generation would inherit the two copies of the defective gene needed to cause the disorder. According to the statistics, without treatment nearly all would be disabled, and 12 of them would die before age 5. "Glutaric aciduria is a treatable disease, so we need to know who is at risk during the first few days of life," says Morton.

Discovering early just who has glutaric aciduria is more than half the battle. Once the disease is diagnosed, Morton's main task is to put his young patients on a low-protein, high-riboflavin diet to lessen the effects of the disorder and prevent medical complications. If a stricken child can survive to age 5 with this help, he or she typically becomes resistant to the worst of the disease.

Meanwhile, Morton's clinic has become a model for rural health care, reducing hospitalization for the disorders to one-tenth their historic rates. The Amish and Mennonites who use the clinic do not buy medical insurance or subscribe to Medicare, but instead depend on family and community for help. Says Dr. C. Everett Koop, former U.S. Surgeon General: "Holmes Morton has forced his way into the hearts of the Amish people and, based on that trust, has accomplished a remarkable service."