Some grateful patients would just like to hug George Brewer for developing a powerful, safe treatment for the genetic disorder called Wilson's disease. Maybe they should also hug a sheep.

Early in this century, ranchers in Australia and New Zealand noticed that their sheep and cattle came down with a strange disease when they grazed on certain pastures. Two observations held clues to what was causing the disease, but it took decades of scientific sleuthing to put the story together. The animals suffered from copper deficiencies. The pastures where they grazed had high levels of the element molybdenum in the soil. Someone eventually figured out that sulfur-a natural component of grass-was combining with the molybdenum to form a complex that blocked copper absorption. The complex came in several forms, but one, called tetrathiomolybdate (TM), was the most potent.

"That's where we came in," says Brewer, who holds joint professorships in human genetics and internal medicine at U-M. Perhaps, thought Brewer and colleagues, TM would help patient's with Wilson's disease, a condition that interferes with the body's ability to excrete copper. If untreated, the copper collects in the liver and brain, causing severe damage. By binding with excess copper in the bloodstream and in the intestinal tract, TM might prevent the copper from being taken into the body.

Good hunch. TM, it turns out, quickly lowers patient's copper levels without unpleasant side effects. Then zinc acetate, another drug pioneered by Brewer, can be used to keep copper levels in check over the long term.--Nancy Ross-Flanigan