Gene Editing with CRISPR Holds Promise for Rare Eye Disease Treatment

Like any new scientific development, CRISPR is often in the news for all the wrong reasons. Don’t get me wrong, there are some very good reasons to fear gene editing, but it’s not all designer babies. Gene editing holds real promise as a revolutionary medical treatment. Imagine deleting the genes responsible for the many heritable diseases that cause devastating pain; it’s perhaps the most efficacious preventative measure possible to take. Developments are constant, so whether you’re working in the US healthcare system, enrolled in any family nurse practitioner online programs, or want to learn more about this promising research, this article is your guide to CRISPR and some of the cutting-edge research that is going on as we speak. 

What is CRISPR?

Clustered Regularly Interspaced Short Palindromic Repeats, better known as CRISPR, is a groundbreaking technology used for gene editing. It was originally adapted from naturally occurring genome editing systems in bacteria. CRISPR lets us pinpoint exact parts of the DNA sequence and remove or change them. The main use of CRISPR is to edit DNA, but it can also be used to regulate genes by turning them on or off without altering their sequence. 

Central to CRISPR’s function are various ‘Cas’ proteins, particularly Cas9, which can be programmed to target almost any DNA sequence; these Cas proteins can locate and cut DNA sequences so that they can be modified or replaced. 

This technology has revolutionized genome editing, making it affordable and accessible for modifying plants and animals. It holds significant promise for advancing scientific research and transforming medicine by treating and potentially preventing numerous diseases. The significance of the CRISPR-Cas9 technique was underscored by the awarding of the Nobel Prize in Chemistry in 2020 to Emmanuelle Charpentier and Jennifer Doudna.

Leber congenital amaurosis

So far, CRISPR has shown promise for treating diseases varying from leukemia, HIV, Sickle cell, and many cancers to heart disease and blood disorders. The beauty of CRISPR is how vast the possible applications are; it is one of the most versatile tools for treatment. New research at the University of Oregon has shown promise for a rare eye disorder. Leber congenital amaurosis, better known as LCA, is an inherited retinal disease. Unfortunately, it’s the leading cause of inherited blindness worldwide. 

Signs of LCA start to show from a young age; babies with LCA are born with genetic mutations that impair the development of their retinas, leading to malfunctioning photoreceptors. This results in reduced electrical activity in the retinas and, consequently, diminished or absent vision. Symptoms of LCA usually start to appear in infants under a year old. They can include frequent eye rubbing, light sensitivity, eye shaking, a cone-shaped cornea (keratoconus), and farsightedness. To get a good diagnosis, a specialist will carry out a thorough examination using electroretinography (ERG) to measure retinal electrical activity and rule out other, more common disorders.

CRISPR and LCA

How does CRISPR fit into all this? Well, instead of diagnosing with an ERG, we could actually go straight to the genetic material that causes this painful disease. Since LCA is inherited, research has shown that it is often caused by mutations in specific genes, one of the most common being in the CEP290. This gene instructs the body to create proteins needed for the photoreceptors to function properly. 

The experimental treatment, named EDIT-101, targets and edits the mutation in the CEP290 gene using CRISPR/CAS proteins, which act like scissors to make precise cuts in the DNA, removing the mutations that produce abnormal proteins. Clinical trials demonstrated that EDIT-101 significantly enhances vision outcomes. This groundbreaking research has shown us that CRISPR gene editing could well be a promising treatment for LCA and other genetic eye disorders.

What this means for eye care 

This research marks a significant leap forward in eye care, particularly for genetic eye disorders like LCA. CRISPR gene editing technology offers the potential to treat LCA and similar conditions, which is an incredible breakthrough given the current lack of effective treatments, and no preventative measures that can be taken. 

Early intervention with gene editing could halt or slow the progression of genetic eye diseases, preserving vision and improving a patient’s quality of life significantly. While the focus is currently on LCA, the transferability of these advancements means they could extend to other genetic disorders, opening up new treatment possibilities. 

Emerging applications 

In a recent study at Harvard, researchers used CRISPR gene editing to restore vision loss in mice afflicted with retinitis pigmentosa, a leading cause of blindness in humans. By targeting a mutation in the enzyme PDE6β crucial for visual signaling in the retina, they corrected gene mutations using the CRISPR system, thereby reinstating the enzyme’s activity and preventing photoreceptor death, ultimately restoring normal responses to light. 

Behavioral tests confirmed sustained improved vision in the mice, including successful navigation in visually guided water mazes and typical head movements in response to visual stimuli. Experts suggest that the techniques employed could extend beyond retinitis pigmentosa, potentially paving the way for treating other genetic diseases. This study offers valuable insights into possibilities for patients grappling with this degenerative genetic condition and shows the promise of CRISPR for many inherited conditions. 

The Bottom Line

While the fears of the rich being able to edit their DNA for nefarious purposes could be real, the reality that I think is actually more exciting is one where research can be done on how to apply CRISPR to solve some of humanity’s oldest genetic issues. If humanity can see the good and navigate sometimes challenging ethical issues, the future could be a lot brighter–even visible, for many more people.