Treating Patients One Gene At A Time

CRISPR gene editing is a tool that allows scientists to precisely target and modify the human genome, making it possible to correct mutations and potentially treat genetic causes of disease.

CRISPR creates Cas9, which is like a pair of molecular scissors with a customizable targeting system. Bacteria use it to defend against viral infection by remembering the genetic code of an attacker. They load that code into Cas9, like giving a hunting dog a scent, enabling it to then match up with a viral attacker and chop its genetic information to bits. Think of it like a GPS that has programmed the GPS coordinates to the final destination. In this way, CRISPR manipulates DNA to edit it in a manner that is much more powerful than previous methods, significantly cheaper, and, most importantly, exceptionally precise.

However, the discovery of the CRISPR-Cas microbial adaptive immune system was made by Francisco Mojica in 1993 and has been undergoing development from many scientists around the world since then. However, the only ever application of the gene editing software has been through experimental clinical trials, cancer research, animal research, and agriculture; however, for the first time, this cutting-edge gene editing technique has been used to edit the DNA of a newborn, the first patient to ever receive personalised, groundbreaking gene-editing treatment.

KJ, just two days old, born at the Children's Hospital of Philadelphia, was found to have a rare genetic disorder known as CPS1. It only affects one in 1.3 million babies, which causes dangerous levels of ammonia to build up in the blood, causing brain damage or even death. Approximately 50% of babies pass away within the first week of this disease. KJ has one particular misspelling in one particular place of his DNA sequence, one incorrect letter out of 3 billion letters that is unique to him. After 6 months of developing the treatment, doctors gave KJ his first infusion in February. Doctors at the Children’s Hospital of Philadelphia tailored the treatment for KJ using a technique known as base editing, changing the letters of a DNA sequence without cutting the DNA itself. KJ is showcasing signs of benefit; however, it is still too early for the doctors to fully understand the full impact. However, if successful, this can open the door for treating other genetic diseases, including cystic fibrosis, sickle cell, and Huntington's.

​CRISPR makes it possible to treat the incurable, but what are the risks?

One of the biggest risks of CRISPR is genetic drift. Because genes are being manipulated in the genome (the encyclopedia of all genes in the human body that sits within cells). Potentially, those genes can then be transferred onto other organisms. Once they are transferred to other organisms (passed on from generation to generation), once they have become part of the cycle, then those genes are in the environment. Those changes can lead to antibiotic resistance, incurable diseases, or other mutations that spread to the population and would be very difficult to control.

Whether it will be accessible to all remains to be seen. The current going rate for some CRISPR-based cell therapies costs more than 3 million dollars per patient, but scientists hope to see in the future this rate going down to just tens of thousands of dollars, enabling this technology to be available in the middle to low-income countries, where this technology can essentially leapfrog care and help people with the “incurable” diseases.

First patient to have received CRISPR therapy 

Reference list

Broad Institute (2018). CRISPR Timeline. [online] Broad Institute. Available at: https://www.broadinstitute.org/what-broad/areas-focus/project-spotlight/crispr-timeline.

Children's Hospital of Philadelphia (2025). World’s First Patient Treated with Personalized CRISPR Gene Editing Therapy at Children’s Hospital of Philadelphia. [online] Chop.edu. Available at: https://www.chop.edu/news/worlds-first-patient-treated-personalized-crispr-gene-editing-therapy-childrens-hospital.

Hobbs, B. (2016). CRISPR: The new tool in the gene editing revolution explained. [online] Abc.net.au. Available at: https://www.abc.net.au/news/science/2016-04-08/crispr-gene-editing-technology-explainer/7217782.

Kaiser, J. (2025). Gene-editing therapy made in just 6 months helps baby with life-threatening disease. AAAS Articles DO Group. [online] doi:https://doi.org/10.1126/science.zp4aln0.

Licholai, G. (2018). Is CRISPR Worth the Risk? [online] Yale Insights. Available at: https://insights.som.yale.edu/insights/is-crispr-worth-the-risk.