UPSC Prelims 2021 Question:

In the context of hereditary diseases, 

consider the following statements: 

1. Passing on mitochondrial diseases from parent to child can be prevented by mitochondrial replacement therapy either before or after in vitro fertilization of the egg. 
2. A child inherits mitochondrial diseases entirely from mother and not from father. 
   
   

Which of the statements given above is/are correct?

Explanation:

• Mitochondrial replacement therapy (MRT) is a new form of reproductive in vitro fertilization (IVF). It works on the principle of replacing a woman's abnormal mitochondrial DNA (mt-DNA) with the donor's healthy one.
  
  
• MRT can be done before (maternal spindle transfer (MST) technique) or after (pronuclear transfer technique) fertilization of the egg. So, statement 1 is correct.
  
  
• MRT provides the substitution of defective cytoplasm with cured one to enhance the expectation of pregnancy rates.  During fertilization, cytoplasm cells are inherited from females. Hence, a child inherits mitochondrial diseases entirely from mother and not from father. So, statement 2 is correct.
  
  

Therefore, option (3) is the correct answer.

Subject: Science & Technology | Diseases