Question

Give two types of gene therapy.

Answer 1

There are two forms of gene therapy based on the types of cells in which genes are delivered:

i. Germline gene therapy:

1. In this method, healthy genes can be introduced into germ cells like sperms, eggs, early embryos.
2. It allows the transmission of the modified genetic information to the next generation.
3. Though it is highly effective in counteracting genetic disorders, it is not encouraged for application in human beings due to a variety of technical and ethical reasons.

ii. Somatic cell gene therapy:

1. In this type, the gene is introduced only in somatic cells like bone marrow cells, hepatic cells, fibroblasts endothelium, and pulmonary epithelial cells, central nervous system, endocrine cells, and smooth muscle cells of blood vessels walls.
2. Modification of somatic cells only affects the person being treated and the modified chromosomes cannot be passed on the future generations.
3. Somatic cell gene therapy is the only feasible option and the clinical trials have already employed for the treatment of acquired disorders such as cancer and rheumatoid arthritis and blood disorders including SCID, Gaucher’s disease, familial hypercholesterolemia, hemophilia, phenylketonuria, cystic fibrosis, sickle cell anemia, Duchenne muscular dystrophy, emphysema, thalassemia, etc.