Question

What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.

Answer 1

Gene therapy is the process of introduction of DNA into an organism e.g. human beings in order to treat a disease. It is used to replace a missing gene product or to correct mutant alleles. ADA is an autosomal-recessive inherited disorder that occurs due to defective adenosine deaminase (ADA) enzyme. Please with this enzyme deficiency suffer from severe combined immunodeficiency (SCID) conditions. Human gene therapy trial can be used for ex vivo introduction of functional ADA gene in bone marrow cells of the patient, suffering from SCID. For this process, an engineered retrovirus containing a functional ADA gene is used to transfer the ADA gene into stem cells isolated from the patient with SCID. The treated cells or modified cells with the good ADA gene are reintroduced into the patient’s marrow.