Stargardt macular dystrophy is a genetic disease that causes juvenile blindness. In the most common form of the disease, a mutation occurs in the ABCA4 gene, which encodes for a protein that is expressed in the eye's photoreceptor cells and is required for the removal of lipofuscin, a toxic byproduct of the visual metabolic cycle.
In patients with mutant ABCA4, lipofuscin accumulates in the photoreceptors, leading to retinal degeneration. Replacement of the defective ABCA4 gene could rescue the photoreceptors and provide a cure for Stargardt's disease.
In a recent issue of the Journal of Clinical Investigation, a research team at the University of Oklahoma Health Sciences Center in Oklahoma City describes a new method to replace the ABCA4 gene in mice. Researchers led by Muna Naash injected a DNA nanoparticle encoding ABCA4 directly into the retinas of the mice.
The mice had detectable levels of ABCA4 for up to 8 months and had improved visual responses compared to untreated animals.
These studies demonstrate that DNA nanoparticles may be a useful technology in the treatment of genetic diseases.
Reference: Zongchao Han, Shannon M. Conley, Rasha S. Makkia, Mark J. Cooper, Muna I. Naash, 'DNA nanoparticle-mediated ABCA4 delivery rescues Stargardt dystrophy in mice', J Clin Invest. 2012; doi:10.1172/JCI64833 (open access)