Fetal hemoglobin can be reactivated in adults to prevent sickling of red blood cells.

“another strategy that people think about um again for the fados who are thinking about that as I mentioned hemoglobin beta uh in terms of the adult form of hemoglobin there's also fetal hemoglobin that's made in utero and so with that that actually has a very tight binding of oxygen because the fetus needs to be able to get oxygen from the maternal blood and it can substitute for adult hemoglobin actually quite efficiently and so one thing one can do is actually turn up the amount of fetal hemoglobin expression and essentially be the insitu version of your gene therapy”