But the discovery that only a few genes are necessary to nudge a human stem cell to develop into a specialized adult cell is encouraging. The finding also underscores the theory that almost any cell of any age in the body can be reprogrammed into any other type of cell, given the right genetic expression.
"It gets us closer to when we are able to use chemicals alone," Eggan said.
Rather than be used for therapy right now, Eggan and Henderson said that the cells they created will be most useful to study the nature and pathology of the disease, particularly in terms of determining what drugs might be effective to treat it.
"Studies... suggest that things are going wrong in those individuals far, far, far before they're ever outwardly sick," Eggan said, referring to a potentially fundamental difference between diseased neurons and normal neurons. "And it's those molecular correlates of disease which will be our first inroads into better understanding of the disease and then, in turn, treatment."