Why in News?  

A nine-month-old became the first to receive a successful custom gene-editing treatment using base editing for a rare genetic disorder, CPS1 deficiency.  

About Gene Editing  

• Gene Editing Therapy is a medical technique that changes the DNA of an organism to fix faulty genes, change how genes work, or add new genetic material.  
• This method gives new hope for curing serious diseases such as sickle cell anaemia, cystic fibrosis, and some types of cancer that are otherwise difficult to treat.  

Two Types of DNA Modification  

• Somatic Gene Editing  
  • Changes the DNA in body (non-reproductive) cells like skin, liver, or blood.  
  • Affects only certain parts of the body in a living person.  
  • Changes affect only that person and are not passed to their children.  
  • Germline Gene Editing  
  • Changes the DNA in reproductive cells (like sperm and egg) or early embryos.  
  • Affects all cells in the resulting baby.  
  • Changes are passed to future generations because the entire body’s DNA is changed.  

(Photo Credit: Reuters; Nature; Massachusetts Institute of Technology)  

Tools Used  

• CRISPR-Cas9 – Uses guide RNA and Cas9 enzyme to cut DNA at exact points.  
• Zinc Finger Nucleases (ZFNs)  
• TALENs