The European Association for Leukodystrophy (ELA) said the breakthrough was unveiled by French researchers at a congress in Rotterdam, the Netherlands, of the European Society of Gene and Cell Therapy.
The therapy targeted faulty genes that cause adrenoloeukodystrophy (ALD), one of a group of inherited disorders known as leukodystrophies in which the protective myeline sheath protecting nerve cells in the brain becomes damaged.
The disease, transmitted through the mother, affects little boys, initially affecting their speech, coordination and socialising, and leads to progressive dementia and death, usually within a decade after the onset of symptoms.
A team led by Patrick Aubourg, a professor at the Saint Vincent de Paul Hospital in Paris, used a harmless version of the AIDS virus as a Trojan horse, introducing the corrected gene to fix the flawed chromosome in bone marrow taken from the children.
The bone marrow was then reinjected into the patients.
ALD occurs because a flawed gene on the child's X chromosome does not produce a key enzyme to break down an accumulation of so-called very long chain fatty acids in the brain.
Six months after the therapy, the results have been encouraging, showing a pickup in production of this enzyme, ELA said.
"Lorenzo's Oil," a 1992 drama starring Nick Nolte and Susan Sarendon, shows the dogged bid of two parents to devise an oil with fatty acids that can block myelin destruction.