Yes, this disorder is genetic by birth (and thankfully one of the rarest disorders known to medicine); but consider this: what if some Mad Scientist in your story forcefully mutates that specific gene in Rosie to trigger this disorder?
Ooohhhh yes. Since this disorder targets things like damaged tissue and old muscle, Rosie's blood would only accelerate this horrifying process if she were to try curing it this way.
These two may literally be more bark than bite, but they are no less tenacious than everyone else.Forced mutation would be cured, thankfully. Her blood's able to removed fast, forced mutations like Cancer and Body Horror and such.
The main trouble would be in-born genetic disorders, I'm not sure if her blood would work if injected into somebody with Down's Syndrome, or as mentioned, FOP. Since unlike forced mutation, this problem's in the person's entire genetic structure in every DNA-containing cell... the cells would either probably "accept" it as 'natural' and therefore not do anything, or heaven forbid- attempt to kill off every "faulty" cell.
Gotta think about this part... this was something I didn't really expect. The original idea was that her cells would cure genetic syndromes, but then it's not so simple because that would mean forcefully mutating every cell in the receiver's body.
Edit: Most probably, the cells would try to fix direct harm to the body due to genetic mutations (e.g. it would solve the lung problems within a Cystic Fibrosis patient) but it will not be able to alter the DNA.
edited 17th Sep '16 3:19:37 PM by ironcommando
...eheh
Hey, thanks! Yeah, her idea's and experiences are meant to make the most use of her special trait.
Thank goodness that FOP is apparently a genetic mutation. I'm not sure how her blood should react with those, however.
edited 16th Sep '16 10:43:05 PM by ironcommando
...eheh