In a First, Gene Therapy Halts a Fatal Brain Disease

While certainly useful to those persons with the condition, this is also a proof of concept for disorders that have straightforward mutations as their underlying cause...

For the first time, doctors have used gene therapy to stave off a fatal degenerative brain disease, an achievement that some experts had thought impossible.

The key to making the therapy work? One of medicine’s greatest villains: HIV.

The patients were children who had inherited a mutated gene causing a rare disorder, adrenoleukodystrophy, or ALD. Nerve cells in the brain die, and in a few short years, children lose the ability to walk or talk.

They become unable to eat without a feeding tube, to see, hear or think. They usually die within five years of diagnosis.

The disease strikes about one in 20,000 boys; symptoms first occur at an average age of 7. The only treatment is a bone-marrow transplant — if a compatible donor can be found — or a transplant with cord blood, if it was saved at birth.

But such transplants are an onerous and dangerous therapy, with a mortality rate as high as 20 percent. Some who survive are left with lifelong disabilities.

Dr. Salzman, with assistance from her sister, Rachel, and from other scientists, was undeterred. She corralled researchers worldwide, asking why a different sort of virus couldn’t be used to slip a good ALD gene into the boys’ cells.

The best choice, it turned out, was a disabled form of HIV, which can insert genes into human cells more safely than other viral carriers.