Gene therapy can cure ‘bubble boy’ disease

New York, January 29: Showing an improvement that is nothing short of a miracle, the gene therapy cured eight of the ten boys inflicted with the fatal ‘bubble boy’ disease.

Following their progress four years after the treatment ceased, scientists found that they were no longer on medication. All 10 patients were still alive, though two needed further treatment. None showed signs of leukemia or other health problems from the therapy.

Bubble boy disease is an immune disorder formally called severe combined immunodeficiency, or SCID. It is the only disease ever to be cured with gene therapy.

SCID babies are born without the ability to produce disease-fighting immune cells. The best known victim was David, Houston's famous "bubble boy" who lived in a germ-proof enclosure until his death at age 12 in 1984.

SCID is caused by a single mutated gene that leaves boys deficient of an enzyme called adenosine deaminase. The fault lies in a gene on the X chromosome that makes an immune protein called interleukin-2.

The disease affects boys because they only have one X chromosome. The faulty gene stops the development of T cells, a key part of the immune systemdefine. The outcome is either to live in sterile conditions or risk picking up life threatening infections.

There are some SCID treatments, like weekly shots of the enzyme, which are quite expensive. Another alternative is bone marrow transplants that can replenish stem cells responsible for renewing new functional immune cells, allowing patients to live normal lives. But transplant success varies widely as suitable donors are only found in one third of the cases.

Gene therapy for the new study was performed in Italy and Israel. Scientists have warned that cancerdefine is a downside of any gene therapy, such as that for SCID. It uses retroviruses, a type of virus that permanently invades cells, to deliver new genesdefine into a patient's body. In most of the cases, it was done before two years of age.

Dr. Donald Kohn, a SCID expert at Children’s Hospital Los Angeles and the University of Southern California, said scientists are trying to figure out why gene therapy produces a leukemia risk. Nevertheless, gene therapy could prove a boon for other blood cell disorders like sickle disease.