Credit: P. AUBOURG

Science 326, 818–823 (2009)

Researchers have slowed a fatal brain disease by inserting a gene into stem cells and then transplanting them into two patients.

X-linked adrenoleukodystrophy (ALD) is a neurodegenerative disease caused by a mutation in the ABCD1 gene. Patrick Aubourg of the French National Institute for Health and Medical Research (INSERM) in Paris and his colleagues engineered a virus to insert a functioning copy of the gene into the genome of the patients' bone-marrow stem cells. The team then depleted the patients of their bone marrow before infusing them with the repaired cells. Sixteen months later, neural degeneration had stopped in both patients. Two years after therapy, 18% of bone-marrow stem cells in one patient (four cells pictured) carried the working gene (cell with red dots).

For a longer story on this research, see http://go.nature.com/AZP3CC