For gene therapy (in English Gene Therapy) we mean the insertion of genetic material (DNA) inside the cells in order to be able to cure diseases (eg genetic diseases). This insertion procedure is known as transfection.
Having the ability to read and decode DNA, many diseases that in the past did not have a clear cause today are classified as rare genetic diseases. All are accumulated by a defect in one or more genes. The end result that follows is the manifestation of the disease. Starting from this observation, the idea underlying the treatment of this kind of pathology is based on the possibility of modifing the failure of a certain gene to function through the insertion of a copy of the same but fully functional one. This is the concept of gene therapy, a correction of the "instruction booklet" - our DNA - which allows the cell to function properly.