Emergence of Gene

The Emergence of Gene Therapy

At the start of 21st century, gene therapy was introduced as the new way to treat immune system deficiency. During this time, heads turned among the scientific population as gene therapy was marketed as a cure for hereditary diseases.

Genes are the units of heredity in living organisms. They are composed of stretches of DNA and RNA that code for other RNA chains and proteins, one of the chief building blocks of life. Gene therapy is the insertion, alteration, or removal of genes within the cells and biological tissues of a person to treat various forms of disease. Gene therapy can also be used to correct deficient genes that are responsible for the development of diseases.

Despite the field’s speedy emergence, it was forced to come to grips with reality with the passing of 18-year-old Jessie Gelsinger on September 17, 1999. Gelsinger suffered from ornithine transcarbamylase deficiency, an X chromosome linked genetic disease of the liver. He died from having suffered massive immune response triggered by the use of an adenoviral vector (a modified virus) used to transplant the gene for treating his condition into his cells which ultimately led to organ failure.

Today, more than a decade later, researchers have been armed with new long-term data, providing hope that gene therapy may fulfill its long held potential. Two recent studies published on August 25, 2011 showed that “13 of 16 children treated with gene therapy for severe combined immunodeficiency (SCID) actually had their immune systems restored, and one is in remission for leukemia that developed due to the gene therapy treatment.”

Those that are born with SCID do not have a functioning immune system, making them extremely vulnerable to infections – causing even the most minute to be exceptionally threatening.

The best treatment for SCID today is a bone marrow transplant from an immunologically matched sibling. However, parents can be recruited instead as unmatched donors, leaving a success rate of about 70 percent. Gene therapy has reached success levels rivaling, and in some cases surpassing, those of the unmatched donor situations.

“Our papers add to the evidence that gene therapy can be corrective of these conditions, and that it gives long-lasting, robust reconstitution of the immune system,” says author Bobby Gaspar, a physician at the Institute of Child Health at University College London.

Now that researchers have begun establishing a foundation for gene therapy, they are expanding its course to target more immune disorders. It is being used to treat beta-thalassaemia and the X-linked adrenoleukodystrophy in addition to leukemia and a rare eye disorder.

In total, five of 20 children in Paris and London who have received gene therapy for a form of SCID that is linked to the X-chromosome have developed leukemia, and one has died. However, because 19 of the 20 children who received such gene therapy are still alive, Dr. Gaspar contends that gene therapy is the favorable treatment method over the traditional treatment for the X-chromosome linked SCID.

Dr. Gaspar’s research group is now undergoing an international collaboration with research groups from all around the world to see which modified viruses do not possess the cancer-causing component in children with the X-chromosome linked SCID and Wiskott-Aldrich Syndrome, another immune deficiency.

Even though it is still in its infancy, gene therapy is a rising field that holds shadowy expectations for the biomedical advances of tomorrow. Genetics, the larger study of heredity, has helped us understand the encryption of the human genome and let us tie together the similarities between those of all organisms on our planet.

It has paved the way for entire new methodologies such as genetic counseling, the process by which patients at risk of an inherited disease can plan proper courses of action through extensive advising of the consequences and nature of the disorder at hand – holding both diagnostic and supportive aspects for the patient and his or her family.

These advances, however, are only a small aspect of the reasoning abilities we are capable of. As Dr. Gaspar promises, tomorrow brings with it fresh tides in the ocean of scientific sovereignty, provided we view the glass as half full.

PHOTO COURTESY of nature.com