Medical technology3 min read
Genome editing (CRISPR)
CRISPR
Genome editing lets scientists change DNA; its tools act like scissors that cut DNA at a specific spot. In December 2023 the FDA approved the first CRISPR-based therapy, for sickle cell disease, later extending it to transfusion-dependent beta-thalassaemia and to children aged 2 and older.
In the approved therapy, blood stem cells are taken from the patient, edited with CRISPR/Cas9, then returned to settle in the bone marrow. It was approved on 8 December 2023 for patients aged 12 and over with sickle cell disease who have recurrent vaso-occlusive crises, in January 2024 for transfusion-dependent beta thalassaemia, and on 1 July 2026 it was extended to children from age 2.
The therapy's label includes a warning about the "risk of off-target editing", meaning the possibility that editing may cause unintended changes in other parts of the genome. According to NHGRI, most experts agree that germline genome editing should not be done at this stage. Editing directly inside the body is still in trials; see In vivo gene editing.
- In widespread clinical use
- Approved for specific uses
- In clinical trials
- Preclinical
- Concept
One CRISPR-based therapy is FDA-approved for sickle cell disease and transfusion-dependent beta thalassaemia, with the cells edited outside the body.
- Sickle cell diseaseApproved for specific uses
Approved in December 2023 for ages 12 and over, and extended in July 2026 to include ages 2 and over.13
- Transfusion-dependent beta thalassaemiaApproved for specific uses
Approved in January 2024 for ages 12 and over, then the 2026 extension included ages 2 and over.23
- In vivo editingIn clinical trials
In May 2025 the NIH announced the first known case of a personalised CRISPR-based therapy given to a single patient (an infant).4
Status last checked: · What the maturity levels mean
What is it?
Genome editing is a method that lets scientists change DNA in many organisms.
How does it work?
These technologies work like scissors, cutting DNA at a specific location.
In the approved therapy, the patient's cells are edited with CRISPR/Cas9 and then transplanted to settle in the bone marrow.
Where is it used today?
The first FDA-approved therapy using CRISPR/Cas9 is a treatment for sickle cell disease (December 2023), for those with recurrent vaso-occlusive crises.
It was then approved for transfusion-dependent beta thalassaemia (January 2024), and in July 2026 it was extended to children from age 2.
Limits and risks
The label includes a warning about off-target editing, meaning unintended changes in other parts of the genome.
Most experts agree that germline genome editing should not be done at this stage.
Common questions
Questions for your doctor
- Am I or my child eligible for a gene-editing-based therapy?
- What are the known risks, and how is long-term follow-up done?
References
- 1U.S. FDA. FDA Approves First Gene Therapies to Treat Patients with Sickle Cell Disease. www.fda.gov/news-events/press-announcements/fda-approves-first-gene-therapies-treat-patients-sickle-cell-diseaseHealth agencies & guidelines · Accessed 2026-10-08
- 2U.S. FDA. FDA Roundup: January 16, 2024. www.fda.gov/news-events/press-announcements/fda-roundup-january-16-2024Health agencies & guidelines · Accessed 2026-10-08
- 3U.S. FDA. FDA Approves First Gene Therapy for Young Children with Sickle Cell Disease. www.fda.gov/news-events/press-announcements/fda-approves-first-gene-therapy-young-children-sickle-cell-diseaseHealth agencies & guidelines · Accessed 2026-10-08
- 4NIH. Infant with rare, incurable disease is first to successfully receive personalized gene therapy treatment. www.nih.gov/news-events/news-releases/infant-rare-incurable-disease-first-successfully-receive-personalized-gene-therapy-treatmentHealth agencies & guidelines · Accessed 2026-10-08
- 5NHGRI (NIH). What is genome editing?. www.genome.gov/about-genomics/policy-issues/what-is-Genome-EditingHealth agencies & guidelines · Accessed 2026-10-08
Review status: Edited content · Last updated:
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