Gene Therapy Development

India is close to developing a gene therapy for sickle cell disease using CRISPR-Cas9, with expectations of significant progress by January 2025.

CRISPR-Cas9 Technology: Researchers at AIIMS are working on using CRISPR-Cas9, a gene-editing tool, to treat sickle cell disease, making India potentially one of the first countries to implement this method.
The Tribal Affairs Ministry, in collaboration with the Birsa Munda Centre at AIIMS, organized a National Conclave to generate awareness on sickle cell disease.
Current laboratory tests by CSIR-IGIB are crucial for the progress towards patient testing.
The U.S. FDA approved CRISPR-Cas9 technology for cell-based gene therapy to treat sickle cell disease in December 2023, paving the way for similar advancements in India.
One of the main challenges is to make the gene therapy cost-effective for India, as part of the mission to eradicate sickle cell disease by 2047.
Screening Mission: The government aims to conduct over seven crore screenings among vulnerable tribal populations across 17 States and Union Territories, with three crore screenings completed so far.

Genome editing, also known as gene editing, consists of technologies that enable scientists to modify an organism’s DNA. These technologies allow for the addition, removal, or alteration of genetic material at specific locations within the genome.
CRISPR Technology: One of the most advanced tools is the CRISPR-Cas9 system, which allows for precise genome editing. This technology has revolutionized plant breeding, enabling agricultural scientists to insert specific traits into the gene sequence.
Types of Genome Editing: Genome editing is categorized into three types based on the nature of the edits:

SDN 1: Introduces small insertions or deletions in the DNA without adding foreign genetic material.
SDN 2: Uses a small DNA template to create specific changes, still without foreign genetic material.
SDN 3: Involves adding larger DNA elements or full genes from foreign sources, similar to the development of genetically modified organisms (GMOs).

CRISPR-Cas9 is a gene-editing tool inspired by a natural defense mechanism in bacteria to combat viruses using a special protein called Cas9.
It involves editing genes by cutting out faulty parts and replacing them with correct sequences.
CRISPR uses a technique similar to “cut-copy-paste” or “find-replace” in computer programs.
It does not introduce new genes from outside but edits the existing ones.
Often referred to as “Genetic Scissors.”

Identify Problematic Gene Sequence: Scientists first identify the gene sequence causing the problem.
Locate the Sequence: An RNA molecule is programmed to find this specific sequence on the DNA, similar to a search function in a computer.
Cut and Remove: The Cas9 protein cuts the DNA at specific points to remove the faulty sequence.
Replace with Correct Sequence: During the DNA’s natural repair process, scientists provide the correct genetic code, which gets incorporated into the DNA.
Note: This process is highly efficient but not entirely free from errors.

Sickle cell anemia is an inherited blood disorder prevalent among people of African, Arabian, and Indian descent.
It affects hemoglobin, the molecule in red blood cells that carries oxygen throughout the body.
The disease causes hemoglobin molecules to become abnormal, forming hemoglobin S, which distorts red blood cells into a sickle or crescent shape. This distortion blocks blood flow and oxygen delivery to various parts of the body.
Symptoms:
- Severe pain known as sickle cell crises.
- Long-term damage to organs such as the liver, kidneys, lungs, heart, and spleen.
- Potentially fatal complications.
Treatment:
- Medications
- Blood transfusions
- Bone marrow transplants (rarely)

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