A one-time gene therapy can markedly slow the progression of Huntington’s disease, potentially paving the way for the first ever treatment to alter the course of this rare, inherited brain disorder.
In a small trial of 29 people who were in the early stages of Huntington’s-related decline, participants who received a high dose of the therapy directly into their brains saw the disease slow by 75% over three years, compared with those in a control group.
Molecular muzzle
In the case of uniQure’s gene therapy, the treatment uses a harmless virus to deliver the recipe for making a short RNA sequence known as a microRNA directly into cells in the affected parts of the brain. The microRNA is designed to ‘muzzle’ the defective huntingtin gene — and stop the cells producing the faulty protein — by blocking the molecular instructions encoded by the gene, known as mRNA. Once delivered, the virus-encoded instructions stay inside the cells, which continue to produce the therapeutic microRNA. The discovery of microRNAs was feted with a Nobel Prize last year, although the technology has yet to yield any approved medicines.
Administering the treatment requires a lengthy surgery in which clinicians use magnetic resonance imaging to precisely place a cannula through small holes in the skull. The therapy is then infused slowly into the striatum, a part of the brain that is among the first and hardest hit by Huntington’s disease.
Read more: Huntington’s disease treated for first time using gene therapy - Nature