From its discovery in bacteria to life-saving therapies, the CRISPR/Cas system represents one of the most extraordinary examples of how basic research can be transformed into real clinical applications. Challenges remain, but the future of genome editing appears increasingly promising. We are only at the beginning of a revolution that could forever change the way we treat genetic diseases.

From the bacterial immune system to genome editing

Scientific revolutions do not always emerge from cutting-edge high-tech laboratories; sometimes they take shape by studying the most primitive microorganisms on Earth: bacteria.

These remarkable life forms, which have inhabited our planet for billions of years, possess a surprisingly sophisticated defense mechanism: the CRISPR/Cas system.

CRISPR, an acronym for Clustered Regularly Interspaced Short Palindromic Repeats, is a primitive immune system that bacteria use to “remind” the DNA of viruses that have previously infected them. The Cas9 protein can recognize these sequences and specifically cut any DNA molecule with a matching sequence.

In 2012, scientists Jennifer Doudna and Emmanuelle Charpentier had a groundbreaking insight: this “molecular scissors” system could be reprogrammed to cut any desired DNA sequence simply by providing a molecular guide called guide RNA. This discovery transformed CRISPR into an extremely powerful genome-editing tool, simpler, faster, and more cost-effective than previously available techniques.

Applications

In theory, the CRISPR/Cas system could be used to make virtually any modification to the DNA of almost any living organism.

In agriculture, for example, it could be used to produce crops with higher yields or improved drought resistance much faster than traditional breeding methods. It can also be used to add new traits or remove others, such as producing gluten-free wheat or decaffeinated coffee. Recently in the United States, CRISPR was used to create a sweeter tomato, increasing its fructose and glucose content by 30%.

However, it is in the field of medicine that CRISPR/Cas is achieving its most significant successes.

The year 2023 marked a major milestone with FDA approval of the first CRISPR-based therapy: Casgevy, for sickle cell disease and beta-thalassemia. This therapy does not directly correct the defective gene but instead reactivates the production of fetal hemoglobin, which replaces the malfunctioning adult hemoglobin. The result is a dramatic reduction in symptoms and the need for blood transfusions.

New therapies under development

In addition to Casgevy, numerous CRISPR-based therapies are rapidly advancing through clinical trials. Below are some of the most significant:

NTLA-2001 (Intellia Therapeutics)

One of the first in vivo CRISPR therapies ever developed. It treats transthyretin amyloidosis (ATTR), a severe disease caused by the accumulation of misfolded proteins that damage nerves and the heart. The therapy uses lipid nanoparticles to deliver CRISPR directly to the liver, where it disables the ttr gene responsible for the disease.

EDIT-301 (Editas Medicine)

This experimental therapy for sickle cell disease and beta-thalassemia uses an innovative variant called CRISPR-Cas12a. The treatment modifies regulatory regions of the hbg1 and hbg2 genes, reactivating fetal hemoglobin production.

Preliminary data from phase 1 and 2 trials show a significant increase in hemoglobin levels, confirming improved oxygen delivery in treated patients.

VERVE-101 (Verve Therapeutics)

Designed for familial hypercholesterolemia, this therapy permanently disables the pcsk9 gene, which regulates cholesterol levels. By blocking this gene, LDL cholesterol is durably reduced, dramatically lowering cardiovascular risk. The therapy is currently in phase 1 clinical trials.

Eligo Bioscience

This French company applies CRISPR to edit the human microbiome, an entirely new approach. The goal is to selectively target harmful bacteria while preserving beneficial ones, thus reshaping the microbiota.

Its main candidate is being developed for acne treatment, paving the way for targeted therapies against antibiotic-resistant infections and chronic diseases linked to gut dysbiosis.

The first child treated with CRISPR

In 2025, CRISPR left the laboratory and clinical trials to save the a child’s life.

KJ Muldoon, a newborn affected by a rare and severe metabolic disorder, became the first pediatric patient to receive a fully personalized gene-editing therapy.

Thanks to the rapid development of CRISPR technology, within just six months researchers designed and administered a genome-editing therapy delivered via lipid nanoparticles directly to the infant’s liver.

The treatment corrected the q335x gene mutation responsible for the disease. No serious adverse events have been reported, but lifelong monitoring will continue. This case represents a historic breakthrough in personalized medicine, proving that CRISPR can be rapidly adapted for individual patients with ultra-rare diseases, offering new hope for genetic disorder treatments.

A therapeutic revolution that calls for ethical responsibility

The potential of CRISPR/Cas is enormous. If today it can cure rare diseases, tomorrow it may prevent them before symptoms even appear. We are entering the era of predictive and personalized medicine, where therapies are tailored based on genomic knowledge and the ability to edit DNA.

However, this progress raises important ethical questions. Editing somatic cells, non-heritable modifications, is currently considered acceptable. In contrast, editing human germline cells, which pass changes to future generations, remains highly controversial due to biological risks and unpredictable long-term consequences.

Concerns about equity also arise: such advanced therapies may be accessible only to a privileged few, increasing healthcare disparities. Finally, non-therapeutic genetic editing for human “enhancement” opens ethically contentious scenarios.

For these reasons, the scientific community emphasizes the need for shared regulations, transparency, and public dialogue.

The CRISPR journey has just begun, and it must be guided not only by innovation, but also by responsibility.

For further reading

• Jinek M. et al. “A programmable dual-RNA-guided DNA endonuclease in adaptive bacterial immunity.” Science. 2012 Aug 17;337(6096):816-21
• Bharti A. & Mudge J. “Therapeutic applications of CRISPR-Cas9 gene editing.” Front Genome Ed. 2025 Dec 16;7:1724291.
• Li T. et al. “CRISPR/Cas9 therapeutics: progress and prospects.” Signal Transduct Target Ther. 2023 Jan 16;8(1):36.
• Musunuru K. et al. “Patient-Specific In Vivo Gene Editing to Treat a Rare Genetic Disease.” N Engl J Med. 2025 Jun 12;392(22):2235-2243.
• Shinwari ZK. et al. “Ethical Issues Regarding CRISPR Mediated Genome Editing.” Curr Issues Mol Biol. 2018;26:103-110.