Here is how it works, if you want to get specific cells from a patient to study their rare disease and test treatments on those cells. In this case, brain cells – without biopsying a bit of brain – in patients with FD (familial dysautonomia). And don't' forget, that is really the one serious use of iPS or ESC: researching a genetic disease and developing treatments. Talk of so-called direct cell therapies with ESC or iPS cells is just tall tales for journalists to help them sell papers; as we know, only adult stem cells are safe for use in direct cell therapy.
Meantime, back at the lab, Susan Slaugenhaupt, a neurologist at Massachusetts General Hospital, says this technology provides "the ability to examine disease-relevant cell types from patients" for the first time. "You can't get brains from patients and look at these cell types." They even find a promising response in vitro to one of their drugs.
And as the research article in Nature says today: "Our study illustrates the promise of iPSC technology for gaining new insights into human disease pathogenesis and treatment."
And that is the whole point. No ESC has ever given insight into a particular patient's disease, because you would have to clone that patient into his twin embryo first to get its stem cells (which has never been achieved). Why bother, when iPSC is doing the job?
Read today's MIT report at http://www.technologyreview.com/biomedicine/23288/
Or look up the Nature article at doi:10.1038/nature08320