Over the past decades, a completely new approach to the treatment of diseases has appeared. This approach is called gene therapy. The fundamental difference between the new and traditional methods of treatment is that it is aimed at eliminating the root cause of the disease, and not its consequences. At the present stage, gene therapy can be defined as the treatment of hereditary and non-hereditary diseases by introducing genes into the cells of patients in order to purposefully change gene defects or give cells new functions.