Facing Down Brain Diseases With Gene Editing

Almost everyone knows someone impacted by a brain disease, from multiple sclerosis and Parkinson’s disease, to Alzheimer’s and epilepsy. In addition to these more common conditions, however, there are also many life-limiting brain diseases that leave young people debilitated before they even have a chance to start their lives. These diseases, which include conditions like AADC deficiency (sometimes known as pediatric Parkinson’s) and Canavan disease, make it clear just how critical new interventions are, particularly innovative work in gene editing.

An Emerging Field

Gene editing is still very new, but despite its nascent state, there are already a number of different approaches to the practice. The best known of these is CRISPR, but overall CRISPR is not yet well-suited to in vivo use. 

Despite its current limitations, CRISPR has served as the foundation for other gene editing innovations, including using lipid nanoparticles to deliver gene therapy interventions across the blood brain barrier. The blood brain barrier presents a unique set of challenges in terms of delivering treatments, due to its relative impermeability, but it can be crossed using the right mechanisms.

When To Offer Interventions

In addition to identifying the right modalities for delivering gene therapy to treat brain diseases, another challenge for scientists is choosing the right time to provide treatment. Currently, the protocol for treating Canavan disease, a fatal brain disorder, involves injecting viral particles carrying the altered gene directly into the brains of children who have already developed symptoms of the condition. 

On the other hand, the Brain Research Foundation has funded in-utero gene therapy research aimed at preventing the development of Hurler Syndrome, a condition caused by a serious enzyme deficiency. By delivering the gene therapy using an intrauterine approach, such treatments promise to offer children with this genetic abnormality more typical lives by preventing symptoms, rather than addressing them after the fact. 

Genetic Errors And Other Issues

While we have seen definite positive outcomes from gene editing for different brain diseases, it’s important to recognize that there is still a lot that we don’t understand about the practice and it is still very risky. Among the many concerns that researchers have raised so far is the fact that various technological advancements have already significantly altered the human genome, and we don’t know how those modifications will impact the population for generations to come. 

The prime example of such modifications – and the one that has raised the most concerns – arose from an experimental case out of Shenzhen, China. A researcher there has, without significant oversight, created twins with the hopes of making them immune to HIV infection. Unfortunately, because of the ways this researcher employed CRISPR, he not only failed to endow the children with the intended immunity, but has potentially caused other germline alterations that could be passed on to any offspring. This case may be the exception right now, but scientists are acutely aware of how many similar cases there could be in the future.

Gene editing technology has the potential to give children a chance at lives they never would have had, as well as to cure devastating conditions in adults, but that’s only possible if early applications occur with extensive research and oversight. 

We are on the cusp of a medical revolution, but we can’t hurry it across the finish line.