question_answer

Read the following article regarding "Gene therapy" and answer the following question.

The ultimate goal of gene therapy is the gene replacement therapy. Gene replacement therapy permits physiological regulation of the transgenes and elimination of the possibility of insertional activation of other cellular gene which occur at the time of random integration of the foreign gene. At present the current strategy for gene therapy largely centres around gene augmentatious therapy, where the foreign gene replaces the defective or missing gene.

 

(a) What is gene therapy?

(b) How is gene therapy being used in treating ADA deficiency patients?

(c) Mention the cause and the body system affected by ADA deficiency in humans.

(d) Name the vector used for transferring ADA-DNA into the recipient cells in humans. Name the recipients cell.

 

Answer:

(a) Gene therapy involve switching off the defective gene and to substitute a healthy gene copy in a person diagnosed to carry a defective gene.

(b) ADA is caused due to the deletion of gene for adenosine deaminase.

Lymphocytes from patient's blood were grown in a culture and functional ADA and cDNA was introduced in these lymphocytes using a retroviral vector.

Lymphocytes were transferred into the patient's body. Periodic infusion of such genetically engineered lymphocyte is done because these cells are mortal.

For permanent cure, gene isolated from the bone marrow cells producing ADA at early embryonic stage can be possible cure.

(c) ADA is caused due to deletion of gene for adenosine deaminase.

Immune system of body is affected due to this.

(d) Retroviral vector is used to transfer ADA-DNA into the recipient cells of human.

Recipient cells-Lymphocytes.