Mice with Lou Gehrig's disease not quite what the doctors ordered

"There were high expectations," said Robert Baloh of the Cedars-Sinai Medical Center in Los Angeles, who made the new mice. "The problem is, they are still mice. Humans and mice, even if they have the same genetic mutation, get different diseases."

Between 20,000 and 30,000 people in the U.S. have Lou Gehrig's disease, or amyotrophic lateral sclerosis, which kills nerve cells in the spine. It causes paralysis and death, typically within a few years. There is only one treatment, riluzole, which extends live by a couple of months.

Difficulties in transferring treatments from mice to people have long plagued scientists trying to treat Lou Gehrig's and Alzheimer's. That's why researchers were excited when, five years ago, it was discovered that some people with Lou Gehrig's have mutations in a gene called TDP-43. They rushed to make mice with the same mutations, thinking the animals would be an excellent new testing ground.

But problems, such as the intestinal blockage, are arising as scientists work to fully understand the new mice. Nonetheless, the mice could still be useful in testing drugs and should also help researchers understand just how Lou Gehrig's kills nerve cells, experts say. And in the process, scientists are learning just how rigorously they have to characterize a given mouse model, and design treatment studies in those mice, to then have a fair shot at success in the clinic.