Why in News
Scientists in the US have, for the first time, successfully employed a CRISPR-based base editing gene therapy to treat an infant with CPS1 deficiency, a rare genetic disorder that leads to toxic ammonia accumulation.
About CPS1 Deficiency
| Aspect | Details |
|---|---|
| Disorder Name | CPS1 Deficiency (Carbamoyl Phosphate Synthetase I Deficiency) |
| Nature | Rare metabolic disorder |
| Cause | Genetic mutation affecting urea cycle enzyme (CPS1) in the liver |
| Effect | Inability to convert nitrogen to urea → toxic ammonia buildup |
| Symptoms | Vomiting, lethargy, seizures, coma in infants |
| Fatality Risk | High if untreated due to hyperammonemia |
Gene Editing Therapy: Overview
| Aspect | Details |
|---|---|
| Definition | A technique to modify DNA sequences to treat or cure genetic diseases |
| Key Tool | CRISPR-Cas9 – acts as “molecular scissors” to cut and repair DNA |
| Other Tools | TALENs (Transcription Activator-Like Effector Nucleases), ZFNs (Zinc Finger Nucleases) |
| Applications | – Sickle Cell Anemia – Cancer Immunotherapy (e.g., CAR-T) – Agri-biotech |
Base Editing vs Traditional Gene Editing
| Feature | Base Editing | Traditional CRISPR-Cas9 |
|---|---|---|
| Mechanism | Converts one DNA base to another using enzyme fusions | Cuts both strands of DNA to insert or remove sequences |
| Accuracy | High; minimal off-target effects | Moderate; higher risk of off-target mutations |
| DNA Breakage | No double-stranded breaks | Involves double-stranded DNA cuts |
| Example | Changed faulty cytosine to thymine in CPS1-deficient baby | Used in sickle cell treatment, cancer therapy |
| Analogy | Pencil eraser fixing a typo | Scissors and glue to cut and rejoin paper |
Key Breakthrough in This Case
| Element | Details |
|---|---|
| Target Mutation | Faulty DNA base responsible for CPS1 deficiency |
| Technique Used | Base editing (precision conversion of incorrect base) |
| Result | Elimination of toxic ammonia buildup |
| Significance | First-ever successful use of base editing in a living human |
Implications for India
| Dimension | Potential Impact |
|---|---|
| Healthcare | Opens avenues for curing rare genetic disorders in infants |
| Regulation | Need for ethical frameworks on gene-editing therapy |
| R&D | Promotes investment in biotechnology and genetic medicine |
| Skill Development | Scope for training Indian scientists in CRISPR and base-editing tools |
Prelims-Based Questions (MCQs)
Q1. Consider the following statements regarding CPS1 Deficiency:
- It is a disorder of the respiratory system.
- It leads to the accumulation of toxic levels of ammonia in the body.
- It is caused due to a mutation affecting the urea cycle in the liver.
Which of the statements given above is/are correct?
A) 1 and 2 only
B) 2 and 3 only
C) 1 and 3 only
D) 1, 2 and 3
Answer: B) 2 and 3 only
Q2. Which of the following correctly distinguishes Base Editing from Traditional CRISPR-Cas9 Editing?
A) Base editing creates double-strand breaks in DNA.
B) Base editing uses scissors and glue to repair DNA segments.
C) Base editing allows conversion of one base into another without cutting both DNA strands.
D) Traditional CRISPR is more accurate than base editing.
Answer: C) Base editing allows conversion of one base into another without cutting both DNA strands.
Q3. Which of the following are gene editing tools?
- CRISPR-Cas9
- TALENs
- ZFNs
- RNAi
Select the correct answer using the code below:
A) 1 and 4 only
B) 1, 2 and 3 only
C) 2, 3 and 4 only
D) All four
Answer: B) 1, 2 and 3 only
Mains Question (GS Paper III – Science and Technology)
Q.“Gene editing technologies like CRISPR and base editing are revolutionizing personalized medicine.”
Discuss the scientific basis, recent breakthroughs, and the ethical and regulatory challenges associated with their use in India. (250 words)
