Using the CRISPR-Cas9 system, Massachusetts Institute of Technology researchers were able to correct a mutation in a mouse model of the human disease hereditary tyrosinemia, a fatal genetic disease.
As they report in Nature Biotechnology, they designed three sgRNAs targeting the region surrounding FAH, the gene encoding fumarylacetoacetate hydrolase that is mutated in the disease. Those guide RNA strands were then delivered to adult mice along with the Cas9 gene and a DNA template with the non-mutated form of the FAH gene.
This led to the expression of the wild-type FAH protein in about one out of every 250 hepatocytes, the researchers report, and the expansion of those hepatocytes led to the rescue of the body weight loss phenotype.
"What's exciting about this approach is that we can actually correct a defective gene in a living adult animal," Daniel Anderson, an associate professor of chemical engineering at MIT and the senior author of the paper, says in a statement.