Describe 'gene therapy' as an example of a current application of genetic engineering in the production of medical treatments.

Gene therapy is a method for treating diseases in which
the cells of a patient's body are provided with a normal gene to make up for a defective
or missing gene.  The technique either to correct a defect in a patient's cells or to
instruct the cells to carry out a new function.

The
technique of gene therapy is still in the early stages of development and is not used
that commonly.  But it offers hope for effective treatment in future of treating
diseases such as sickle cell anaemia, AIDS, cystic fibrosis, and some forms of cancer,
that are incurable today.

Gene therapy consists of three main
steps:

(1) Removing some cells from the patient's
body.

(2) Inserting a corrective gene from another
individual or organism into these cells.

(3) Returning the
altered cells to the body.

The altered cells are returned
to the patient's body by means of a vector, which is the name given to any substance or
piece of equipment capable of carrying therapeutic genes to the cells that need
them.

Once altered cells are in the body of the patient,
the new genes automatically begin to treat the disease. This 3 step process is repeated
until the body maintains its own supply of the new gene through normal cell
growth.

Gene therapy was first used in 1990 at the U.S.
National Institutes of Health.

The use of gene therapy has
evoked controversial responses from knowledgeable people.  Some people fear that gene
therapy may permanently alter the basic substance of human beings if genes from other
species are used. In view of such possibilities, it is desirable for governments to
monitor and control its use.