CRISPR Gene Editing and Its Role in Combating Rare Diseases

By Owolabi Suleiman @Stark MD_Tech and Medicine News

In the rapidly evolving landscape of biotechnology, CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) gene editing stands out as a revolutionary tool with the potential to transform how we treat rare genetic disorders. Often described as "molecular scissors," CRISPR-Cas9 technology allows scientists to make precise changes to DNA, correcting mutations that cause diseases at their genetic root. This approach is particularly promising for rare diseases, which affect fewer than 200,000 people in the US (or equivalent thresholds globally) and often lack effective treatments due to their complexity and low prevalence. With over 7,000 known rare diseases impacting an estimated 300 million people worldwide, including many in regions like West Africa where conditions such as sickle cell disease are more common, CRISPR offers hope for personalized 

Understanding CRISPR: 

The Basics CRISPR-Cas9, derived from bacterial immune systems, works by using a guide RNA to target specific DNA sequences. The Cas9 enzyme then cuts the DNA at that site, enabling repairs, insertions, or deletions. Advanced variants like base editing (which changes single DNA letters without full cuts) and prime editing further enhance precision, reducing risks like off-target  For rare diseases, often caused by single-gene mutations, this means potentially curing the condition rather than just managing symptoms. Unlike traditional therapies, CRISPR can address the underlying genetic cause, making it a game-changer for disorders with no cures.

Breakthroughs in Treating Rare Diseases

The first major milestone came in late 2023 with the approval of Casgevy (exagamglogene autotemcel), the world's first CRISPR-based therapy for sickle cell disease (SCD) and transfusion-dependent beta-thalassemia (TDT). Developed by CRISPR Therapeutics and Vertex Pharmaceuticals, it edits patients' hematopoietic stem cells to boost fetal hemoglobin production, alleviating severe symptoms. By 2024, approvals expanded to the US, UK, EU, Saudi Arabia, Bahrain, and Canada, with over 75 patients showing promising results in trials.

A rare blood disorder affecting millions globally (with high incidence in Nigeria and sub-Saharan Africa), exemplifies how CRISPR can turn a lifelong condition into a manageable or curable one.

Beyond blood disorders, CRISPR is tackling ultra-rare conditions. In 2025, a groundbreaking case at Children's Hospital of Philadelphia treated a baby with severe carbamoyl phosphate synthetase 1 (CPS1) deficiency—a life-threatening metabolic disorder occurring in just one in a million births—using a customized base editor. Delivered via lipid nanoparticles, it corrected the mutation in liver cells, easing symptoms and marking the first personalized CRISPR therapy for such a rare disease.This "n-of-1" approach (tailored to one patient) highlights CRISPR's flexibility for diseases too rare for broad drug development.

Other targets include:

•Muscular Dystrophy: CRISPR edits dystrophin gene mutations, with preclinical models showing muscle function restoration.

•Cystic Fibrosis: Gene corrections in lung cells aim to fix CFTR mutations, potentially reducing chronic infections.

•Hemophilia and Immunodeficiencies**: In vivo editing trials are underway, inserting functional genes to produce missing proteins.

•Neurological Disorders: Emerging tools like epigenome editors are silencing faulty genes in conditions like Angelman syndrome, with brain-targeted delivery advancing toward clinical use.

As of early 2026, there are 239 CRISPR-related clinical trials worldwide, with 152 active. Rare diseases dominate the pipeline, including metabolic, eye, and neurological conditions. Phase 3 trials for hereditary angioedema and amyloidosis signal more approvals soon.

Recent Advancements and Challenges

2024-2025 saw innovations addressing CRISPR's limitations. Researchers at the Broad Institute developed "light-activated" controls to minimize off-target cuts, improving safety for therapies. In vivo editing (direct body delivery) is progressing, especially for liver and brain diseases, reducing the need for invasive procedures like bone marrow transplants.

However, challenges remain: High costs (Casgevy exceeds $2 million per treatment) raise equity concerns, particularly in low-resource areas like Nigeria. Off-target effects, ethical issues, and delivery to hard-to-reach tissues (e.g., the brain) are ongoing hurdles. Regulatory adaptations for rare diseases are crucial to accelerate trials.

The Future Outlook

Experts predict CRISPR will cure more rare diseases in the next decade, with CRISPR-Cas9 leading the way. Integration with AI for mutation prediction and nanoparticle delivery could enable treatments for cancers, autoimmunities, and even polygenic disorders. For global health, initiatives like WHO collaborations aim to make these therapies accessible, potentially reducing the burden of rare diseases in Africa and beyond.

In summary, CRISPR is shifting rare disease treatment from palliative care to cures, offering unprecedented hope. As research advances, it could redefine medicine, but ensuring equitable access will be key to its success.