<P> In March, French scientists reported on clinical research of gene therapy to treat sickle - cell disease . </P> <P> In August, the FDA approved tisagenlecleucel for acute lymphoblastic leukemia . Tisagenlecleucel is an adoptive cell transfer therapy for B - cell acute lymphoblastic leukemia; T cells from a person with cancer are removed, genetically engineered to make a specific T - cell receptor (a chimeric T cell receptor, or "CAR - T") that reacts to the cancer, and are administered back to the person . The T cells are engineered to target a protein called CD19 that is common on B cells . This is the first form of gene therapy to be approved in the United States . In October, a similar therapy called axicabtagene ciloleucel was approved for lymphoma . </P> <P> In December the results of using an adeno - associated virus with blood clotting factor VIII to treat nine haemophilia A patients were published . Six of the seven patients on the high dose regime increased the level of the blood clotting VIII to normal levels . The low and medium dose regimes had no effect on the patient's blood clotting levels . </P> <P> In December, the FDA approved Luxturna, the first in vivo gene therapy, for the treatment of blindness due to Leber's congenital amaurosis . The cost of this treatment was speculated to be one million US dollars . CRISPR gene editing technology has also been used on mice to treat deafness due to the DFNA36 mutation, which also affects humans . </P>

What are genes that are undergoing gene therapy