Innovations in Biotechnology and Medical Sciences

CRISPR’s Breakthrough in Treating Blindness


From UPSC perspective, the following things are important :

Prelims level: LCA, CRISPR Cas9;

Mains level: NA

Why in the news?

Scientists have successfully used CRISPR-Cas9 gene editing to restore vision in individuals with a rare form of inherited or congenital blindness.

  • The groundbreaking clinical trial, named “BRILLIANCE,” demonstrated promising results in improving vision and quality of life for participants with Leber congenital amaurosis (LCA), a severe vision disorder.

What is Leber Congenital Amaurosis (LCA)?

  • LCA is a rare genetic disorder that primarily affects the retina the ‘light-sensitive’ tissue at the back of the eye. It leads to severe visual impairment or blindness at birth or within the first few months of life.
  • It is inherited in an autosomal recessive manner, meaning a child needs to inherit one defective gene from each parent to develop the condition.
  • There are several genes associated with LCA, with mutations in at least 14 different genes known to cause the disorder.
  • These genes generally affect the development and function of photoreceptors or the retinal pigment.

Key highlights of the BRILLIANCE trial:

  • The BRILLIANCE trial involved 12 adults and two children diagnosed with LCA, a condition characterized by early-onset vision loss.
  • Participants received a single dose of a CRISPR gene therapy called EDIT-101, designed to correct mutations in the CEP290 gene responsible for LCA.
  • In this case, CRISPR-Cas9 cuts out the faulty DNA segment in the CEP290 gene and replaces it with a healthy DNA sequence, restoring the function of the CEP290 protein crucial for vision.
  • Out of 14 participants, 11 experienced improved vision without serious side effects.

Back2Basics: CRISPR-Cas9 Gene Editing

  • CRISPR-Cas9 stands for Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated protein 9.
  • It is a technology that allows geneticists and researchers to edit parts of the genome by altering sections of the DNA sequence.
  • Emmanuelle Charpentier and Jennifer Doudna’s work on CRISPR-Cas9 as a ‘molecular scissor’ earned them the 2020 Nobel Prize in chemistry.
  • The system consists of two key components:
  1. Cas9: This is the enzyme that acts like a pair of molecular scissors. It is responsible for cutting the DNA strand at a specific location, allowing for the removal, addition, or alteration of DNA at that site.
  2. Guide RNA (gRNA): This is a piece of RNA that is designed to find and bind to a specific sequence of DNA that matches its code. The gRNA guides the Cas9 enzyme to the exact spot in the genome where an edit is desired.
  • Mechanism:
    • The process begins with the design of a gRNA that matches the DNA sequence where an edit is needed.
    • Once inside the cell, the Cas9 enzyme and the gRNA form a complex that can identify and bind to the target DNA sequence.
    • The Cas9 then cuts the DNA at this location.
    • After the DNA is cut, the cell’s natural repair mechanisms can be harnessed to add or remove genetic material, or to make specific changes to the DNA.



[2019] What is Cas9 Protein that is often mentioned in news?

(a) A molecular scissors used in targeted gene editing

(b) A biosensor used in the accurate detection of pathogens in patients

(c) A gene that makes plants pest-resistant

(d) A herbicidal substance synthesized in genetically modified crops

Get an IAS/IPS ranker as your 1: 1 personal mentor for UPSC 2024

Attend Now

Notify of
Inline Feedbacks
View all comments


Join us across Social Media platforms.

💥Mentorship New Batch Launch
💥Mentorship New Batch Launch