Dogs with Duchenne muscular dystrophy (DMD) were treated with the CRISPR genome editor to restore production of the missing protein responsible for the disease. The dogs showed obvious signs of behavioral improvement such as running and jumping. DMD is an x-linked genetic disorder that affects about 1/3600 boys worldwide. Progressive muscle degeneration and weakening can begin as early as 3 years old and affect every muscle in the body, eventually leading to life threatening complications from heart and respiratory muscle weakness. This study used DMD beagles with a genetic mutation similar to the most common mutation in humans, making it an important model for the clinical translation of CRISPR gene editing
In this study, four 1-month-old beagles were treated with dystrophin-targeted CRISPR either directly in a leg muscle (2 dogs) or intravenously at either a low or high dose (the other 2 dogs). Six weeks after muscle injection, the dogs’ leg muscle was making dystrophin at about 60% of healthy levels, compared to almost none pre-treatment. After 8 weeks, the dog treated intravenously with a high dose made dystrophin at 5-92% of healthy levels in various muscles, notably 92% in the heart and an average of 50% restoration in three leg muscles. Long-term studies with more dogs are needed for verification before even considering clinical trials.