A way to treat genetic disease without editing the genome

A network of activated genes in the muscles of Duchenne muscular dystrophy mice.
The Belmonte lab's advanced in vivo Cas9-based epigenetic gene activation system enhances skeletal muscle mass and fiber size growth in a treated mouse (right) compared with an independent control (left). The fluorescent microscopy images show purple staining of the laminin glycoprotein in tibialis anterior muscle fibers. (Credit: Salk Institute)

Soon, we might not just be editing DNA itself, but how and when the genes it encodes are expressed. In a paper published Thursday in the journal Cell, scientists from the Salk Institute report using the gene-editing tool CRISPR in mice to alleviate symptoms of type 1 diabetes and Duchenne muscular dystrophy, without making edits to the actual genome. Instead, they used CRISPR to turn the genes on and off.

Why it matters: Genetic editing to treat disease raises questions about the ethics of permanently changing someone’s DNA. These edits are reversible. CRISPR also involves cutting both strands of DNA, which some scientists are concerned could lead to unexpected and unwanted mutations. By altering the expression of genes rather than the genetic material itself, researchers hope to avoid these potential problems and treat diseases that aren't caused by genetic mutations.