>> well, the question is once one has a disease-causing gene, can one use that both to unrsta theisea and ultimately, of course, to find therapy. and the answer is that thus far there have been huge insights, enormous insights into the complexity of how a motor neuron dies when there's a mutant gene. but the ability to use that information therapeutically is still not yet realized. >> this has been true time and time again. that even when we know the gene, even when we know what is called the mechanism of path though genesis, how that gene does its damage, that mutant gene, we're stale long way if treatment. it tes a long time and they williscu rious therapeutic approaches that are possible in order to ameliorate the disease. it's a very difficult challenge. >> rose: any therapies in terms of stem cell or any other area of... >> we think that there are a variety of therapies that are very promising. i'll give you one or two examples. so typically in most of the a.l.s. genes that have been found so far, the concept is that the mutant gene makes a toxic protein and that wreaks havoc in