Hm... An item which fixes the genetic damage, be it congenital or acquired? Sounds like space Debimbo. I actually want to make one, but I'm quite sure that bimbofication effects are intended to be uncurable.
I think mental one effects are uncurable. Physical as been show by Savin replies in other thread aren't pernament (he said Treated PC can go from full female to full male frame and back without trouble). So it seems in TiTS so far we not have uncurable physical changes only mental ones.