In a rural Wisconsin village, the doctor makes house calls - and sees some of the rarest diseases on Earth

When James DeLine chose the life of a country doctor, he had no experience treating the Amish, and no idea they would take his work to the leading edge of genetic medicine. It is 5 degrees below zero and a light powdering of snow swirls across the roads of Vernon County. A few horses and buggies clop through the chill morning air, but Perry Hochstetler leaves his buggy at the family farm and has a driver take him to his doctor’s appointment.