Through gene therapy they have managed to cure phenylketonuria in the mouse. The new one is the method used. In fact, the genes that are cured have been introduced into the DNA of mice through a virus protein and not through the entire virus. Thanks to this, genes enter a specific place of DNA. On the contrary, with the use of all the virus, they enter anywhere, which generates problems, since they can prevent the expression of common genes. For example, leukemia was developed by ten children who were treated in France. Research has been conducted at Standford University.