Scientists have developed a genetic therapy to treat two rare childhood diseases using a component of the HIV virus.

The research, which was detailed in two studies published in Science on June 11, showed that scientists were able to use an HIV virus vector -- which acts as a tool to help put genetic material into cells -- on three children with metachromatic leukodystrophy and three others with Wiskott-Aldrich syndrome. Their diseases have stopped progressing and some of the patients have stopped showing symptoms for 18 to 32 months following the therapy.

Using a vector of the virus, the mechanism in which it gets into cells, is not the same as giving the children the actual HIV virus.

"Three years after the start of the clinical trial, the results obtained from the first six patients are very encouraging. The therapy is not only safe, but also effective and able to change the clinical history of these severe diseases," author Luigi Naldini, a researcher from the San Raffaele Telethon Institute for Gene Therapy, said in a press release.

Metachromatic leukodystrophy is an inherited genetic mutation that causes fats called sulfatides to collect in cells, especially in those that produce a substance that surrounds and protects nerves, called myelin. In patients with the disorder, the sulfatide collection ends up destroying the white matter that makes up part of the nervous system. This affects the brain, spinal chord and sensory cells that registered touch, pain, heat and sound.

Eventually the patients no longer have cognitive functions or motor skills, and they cannot feel different sensations. Other symptoms include seizures, paralysis, inability to speak, blindness, hearing loss and eventually loss of awareness. There is currently no cure.

About one out of 40,000 to 160,000 people worldwide have the disorder, the National Institutes of Health reports. The most common form of the condition, called late infantile form, affects 50 to 60 percent of people with the disorder starting at about 2 years old. Twenty to 30 percent of patients will have a juvenile form which begins to manifest around the age of 4 through adolescence. The adult form affects 15 to 20 percent of patients with metachromatic leukodystrophy, and starts appearing during teenage years or later.

People with Wiskott-Aldrich syndrome do not have a normal immune system and have a harder time creating blood clots. The disease, which is caused by an inherited genetic mutation on the X chromosome, causes abnormal or nonfunctional white blood cells, which puts the patients at risk of immune and inflammatory disorders.

The condition is typically found in males, and has an incidence of 1 to 10 cases per one million males, the NIH said. It is rarely found in women. Wiskott-Aldrich can be treated if the patients receive a bone marrow or stem cell transplant, which can work very well if the donation is a close match.

The researchers used an HIV virus vector to insert a corrected form of defective genes at the root of these diseases into the patients' own blood stem cells. Then, the healthy blood stem cells were surgically implanted in to the subject.

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Gene therapy using part of HIV virus treats two rare childhood diseases

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