subject: Is Gene Therapy The Answer? [print this page] Since the 1960s, researchers have been interested in gene therapy, an approach believed to be an effective method of curing a genetic disease by inserting a "therapeutic" or normal human gene into a defective cell.
Also known as stem cell, the therapy that employ genes is founded on the theory that 'therapeutic' or 'good' genes can replace or repair 'bad' or 'faulty' or 'defective' genes in an individual. Especially benefiting from the said therapy is the genetic diseases which afflict 5% of the world population to date. At a later stage in one's life, around one in ten people will develop or has already developed the inherited genetic disorder. The chances of having the genetic disorder can be measured by the types of genes present in that person, or the genes inherited from his or her parents.
With the exception of the male sex chromosomes, all of us carry tow copies of all genes, each derived from our father and the other from our mother. Each of the male chromosomes XY has one copy of the genes. In most cases, one copy of gene is sufficient to prevent the development of a disease so that if the faulty gene is recessive, its counterpart will perform all the essential tasks which are normally assigned to two copies. However, should we inherit the same recessive gene from our father and mother, we are likely to contract the genetic disorder.
If the defective gene is dominant, it can cause the disease despite having a normal counterpart. An example of a dominant disease is the Huntington's chorea, a severe nervous system disorder, which can affect only the children whose parents also had the disease.
With gene therapy, scientists believe that a faulty gene or the absent gene can be replaced by a functional gene inserted into the target cell so that the body can do the necessary correction of the protein or enzyme, and thus reduce or remove the root cause of the disease.
The targets of this approach are the diseases which are very rare that humans are unable to manufacture a specific enzyme, and which the insertion of a normal gene into only one organ is the only treatment. An example to this is the Lesch-Nyhan syndrome, a disorder that can make the patient do absurd actions such as severe biting of fingers and lips.
The Phenylketonuria or PKU, a disease that affect one in every 12, ooo white children is an example of a disease in which the normal gene should be delivered to solely one organ. Caused by a faulty gene producing a liver enzyme, PKU can lead to severe mental retardation when not treated early.
The tissues that most types of gene therapy can cure are somatic, which include all the cells in the human body, except the egg and sperm cells. In germline cells, which provide the children's genetic heritage, the gene therapy may affect both the patient being treated and his or her children. It would affect the genetic makeup of the whole human species, as well as the future generation.
