Scientists halt brain disease with new gene therapy

By Kate Kelland

LONDON (Reuters) - Scientists have managed to halt a rare and fatal brain disease with an experimental gene therapy technique using a deactivated version of the AIDS virus, a study published on Thursday showed.

The international team used a disabled form of human immunodeficiency virus (HIV) to deliver working genes to two boys with the brain disease X-linked adrenoleukodystrophy (ALD). Their success may help shape future treatment.

Patrick Aubourg of Inserm-University Paris Descartes, who led the study, said it was the first time scientists had successfully used an HIV-derived delivery technique for gene therapy in humans, and the first time gene therapy had been used effectively in a severe brain disease.

"Up to now we have treated two boys ... and we can say with confidence that more than two years after gene therapy their brain disease has been arrested," he said.

Featured in the 1992 movie "Lorenzo's Oil," ALD is a rare hereditary condition caused by a deficiency of a protein involved in fatty acid degradation.

Sufferers gradually lose the myelin sheath, a protective layer coating the brain's nerve fibers, leading to disabilities such as blindness, deafness, seizures and progressive dementia.

X-linked ALD, the most common form, affects boys from around 6 years old, and they usually die before reaching adolescence.

The disease can be halted using bone marrow transplants because the donor marrow includes cells that develop into myelin-producing cells. But finding a matching donor can be difficult and take time, and the transplant is risky.