You may have heard of CRISPR-Cas9. It’s in the science news a lot, and more recently popping up in the medical news. But what is it exactly? CRISPR-Cas9 is an acronym attached to an acronym. It stands for a DNA editing tool discovered and fine-tuned by scientists. CRISPR, pronounced crisper, stands for Clustered Regularly Interspaced Short Palindromic Repeats. Cas9 stands for CRISPR ASsociated protein 9.
The name is pretty confusing, but simply put, it describes two components necessary for the tool to work. CRISPR’s palindrome sequences are a template used to create coordinates. These coordinates guide Cas proteins to the desired DNA sequences. Once there, several different Cas proteins work together to carry out the editing process. CRISPR holds enormous potential in that it can precisely delete, add in, or change any DNA sequence.
To imagine how CRISPR works, think of DNA as our architectural blueprint. It contains all the information required to construct ourselves (and other living things). CRISPR is like a pencil (with one of those really good erasers at the end; the kind that don’t leave any residual smudges). We can use the pencil to erase, add in, or replace a section of genetic blueprint that is broken or damaged.
Damaged or broken DNA, also known as mutations, underlie debilitating and life-threatening disorders and diseases. CRISPR can prevent the development of disorders by editing causative or potentially harmful DNA before problems manifest. Currently ideal candidates for CRISPR include some of the mutations that give rise to cystic fibrosis, sickle-cell anemia, and Duchenne muscular dystrophy.
CRISPR also has the potential to modify existing cells which help cure diseases. This possibility was first demonstrated in a young girl named Layla. Layla was only 3-months old when she was diagnosed with acute lymphoblastic leukemia. This type of leukemia is a cancer that promotes the generation of immature, non-functional white blood cells.
Unfortunately, all traditional treatments failed to work for Layla. At 11-months old, her chances of surviving past her second birthday were non-existent. However, with the encouragement of Layla’s parents, Layla’s doctors reached out to scientists producing white blood cells which had been edited.
The edited white blood cells were generated to enhance their cancer-destructive qualities. An international cohort of scientists and medical doctors worked together to deliver these specialized cells to Layla. Within weeks, Layla’s health began to improve and within months she reached remission. It is too early to label Layla completely cured, but she is now a healthy toddler at 2 and a half years old with no sign of cancer. A second child recently received identical treatment and has also reached remission. These children lived due to the discovery and implementation of gene editing techniques.
Numerous clinical trials in the US and China are currently underway utilizing CRISPR for a variety of other illnesses. (You can see a sampling of US trials currently on the federal register here.) CRISPR provides us the opportunity to undo a life-threatening illness or mutation with a simple erase and rewrite. Responsible implementation of CRISPR could help decrease the frequency of life-debilitating and life-threatening disorders and diseases, and potentially propel us into a future where cancer no longer wreaks havoc. Where children can walk, run, play and enjoy life fully – no matter what genetic mutations they may have inherited or acquired.