France – the team of Pr Aubourg of the Saint-Vincent-of-Paul hospital of Paris succeeded in slowing down the evolution of a serious cerebral disease, the adrenoleukodystrophy (ALD). This rare genetic disease affects the brain of the young children in good health.

The researchers used a combination of gene therapy and cell therapy to slow the progression of the disease in two children suffering from ALD. Nearly three years after the disease progression was slowed and no side effects were observed.

The ALD mainly affects boys between 5 and 12 years. A defective protein causes the destruction of myelin in the central nervous system. Myelin is the sheath surrounding the nerves, allowing the transmission of nerve impulses, ultimately, patients suffering from dementia, motor problems and the disease progresses to death. The only known treatment so far was the bone marrow graft.

The researchers used a corrective gene inserted into stem cells from bone marrow through a virus derived from HIV. The gene correction was then fixed on the X chromosome to correct the defective gene causing the disease. Both patients underwent the same procedure as for transplantation: their marrow has been destroyed to accommodate the stem cells.

Two years later, the correct version of the protein was still present in the nervous system of children. Their status is comparable to that of patients receiving conventional transplantation of bone marrow, the researchers said. This work must now be confirmed in larger scale, but opens the door to new discoveries about other genetic diseases.