Gene therapy – a type of treatment that transplants normal working genes into cells to replace non-working genes in order to treat genetic disorders. There are many ways that gene therapy can be done. Sometimes, a gene with a disease-causing variant can be replaced with a healthy gene. Sometimes, a gene with a disease-causing mutation can be inactivated or “silenced.” And sometimes, a new gene can be put into the body to help fight a disease. Some gene therapies are still experimental.