A molecule that lowers the expression of the mutant protein that causes Huntington's disease reverses symptoms of the disorder in mouse models of the disease.

Don Cleveland at the University of California, San Diego, and his team infused a short string of nucleotides that blocks the expression of the huntingtin gene into the brains of mice bearing the disease-causing mutation. The molecule persisted in brain tissue for more than three months, and levels of mutant protein were reduced for up to four months after the infusion. Nine months post-treatment, the mice continued to show decreased anxiety and improved motor function.

When the oligonucleotide was infused into the cerebrospinal fluid of Rhesus macaques, levels of huntingtin messenger RNA fell in multiple brain regions.

Neuron 74, 1031–1044 (2012)