Dr. Lucie Bruijn, science director of the ALS Association, says the progress being made in this clinical trial is exciting.

CNN: Stem cell treatment goes from lab to operating room

Lucie Bruijn, senior vice president of research and development at the ALS Association, likens this process to building an engine: If there are parts missing or placed in the wrong place or in the wrong way, the engine doesn't work right.

CNN: Gene linked to some cases of Lou Gehrig's disease found

Scientists at Massachusetts General Hospital, the University of Massachusetts and Kings College in London found the mutation by doing detailed sequencing of the genes in several families with an inherited form of ALS. The findings are published in the February 27 issue of the journal Science and were partially funded by the ALS Association.

CNN: Gene linked to some cases of Lou Gehrig's disease found