A genetic disease has been cured in an adult animal for the first time in history.

Scientists at MIT have recorded using a procedure where they edit the DNA of a live adult animal to replace a defective gene that causes liver disease.  The scientists say the procedure, known as Crispr, allows them to edit a single “letter” in the genetic alphabet.

“We basically showed you could use the Crispr system in an animal to cure a genetic disease, and the one we picked was a disease in the liver which is very similar to one found in humans,” said Professor Daniel Anderson.

The MIT team believes because the DNA is so similar, they should be able to begin testing of the Crispr protocol in humans within the next few years.

The process would have to be altered, however, to carry the mutations into the human body via harmless adeno-associated viruses.