The general condition of methemoglobinemia isn't as rare as this family's particular genetic condition, so the methylene blue treatment was already known. I'm n

The general condition of methemoglobinemia isn't as rare as this family's particular genetic condition, so the methylene blue treatment was already known. I'm not sure when they first discovered that methylene blue can treat methemoglobinemia - methylene blue was discovered in 1876, but it does all sorts of things.