For those of you who think that everything cool has already been discovered:
Here is a example of "over promising". Think about it: how would you practically insert XIST into chromosome 23 (and only 23) of many Down patient's cells? Oh, and even if you could- it would be too late because by the time you see the baby, many abnormalies have already manifested to the point of obviously visible. Good basic science otherwise, but the "translational" angle is ridiculous.
I suppose I should look at this through a glass-half-full lens: