Matt had begun to notice problems with his golf swing—particularly in his left arm. He thought it might be a torn rotator cuff, perhaps from playing too much. Then one morning, while pulling a gallon of milk out of the fridge, his strength suddenly gave out. The jug fell to the kitchen floor. At Thanksgiving, Matt’s uncle, a doctor, noticed the shrinking muscles in Matt’s hand and arm and convinced him to see a neurologist at Northwestern University. In January 2000, after a series of tests, the doctor called Matt and Linda to his office.