Mitochondrial Donation Treatment (MDT)

Why in news?

• A baby has been born in the UK using a technique called Mitochondrial Donation Treatment (MDT) (popularly called ‘Three Parents Baby’).

What are Mitochondria?

• Popularly known as the ‘Powerhouse of the cell’, mitochondria are a double membrane-bound organelle found in most eukaryotic organisms.
• They are found inside the cytoplasm and essentially function as the cell’s “digestive system.” They play a major role in breaking down nutrients and generating energy-rich molecules for the cell. Many of the biochemical reactions involved in cellular respiration take place within the mitochondria.

Functions of Mitochondria

• Regulates the metabolic activity of the cell
• Promotes the growth of new cells and cell multiplication
• Helps in detoxifying ammonia in the liver cells
• Plays an important role in apoptosis or programmed cell death
• Responsible for building certain parts of the blood and various hormones like testosterone and oestrogen
• Helps in maintaining an adequate concentration of calcium ions within the compartments of the cell
• It is also involved in various cellular activities like cellular differentiation, cell signalling, cell senescence, controlling the cell cycle and also in cell growth.

About Mitochondrial Donation Treatment (MDT):

• Certain defects might occur impacting the way the mitochondria produce energy for the cells (especially in the ‘energy-hungry’ tissues of the brain, nerves, muscles, kidneys, heart, liver), and thereby impacting cell function.
• The diseases that arise out of such mitochondrial mutations are called mitochondrial diseases.
• Some estimates put the incidence of mitochondrial diseases as one in 5,000 people.
• Mitochondrial diseases are only passed on by the mother to their children.
• In this case, the mother had mitochondrial disease, and she was intent on not passing it on to her baby. She also did not want to have a donor egg, for the baby would carry the genetic material of the donor. So, they went for Mitochondrial Donation Treatment (MDT).

How does Mitochondrial Donation Treatment (MDT) work?

• Through an advanced in vitro fertilisation technique, the baby’s biological father’s sperm was used to fertilize the eggs from the biological mother, who has mitochondrial disease and a third, female donor with clear mitochondria, separately.
• Then, the nuclear genetic material from the donor’s egg is removed and replaced with the genetic material from the biological parents.
• The final product — the egg — which has the genetic material (DNA) from the parents and the mitochondria from the female donor, is implanted in the uterus and carried to full term to yield a baby who will be free from the mother’s mitochondrial disease. This process is termed Mitochondrial Donation Treatment (MDT).

Side effects of MDT:

• Sometimes it is possible that a small amount of the maternal mitochondria with errors may get passed on during the procedure. However, more data is needed to establish consensus on this.

PRACTICE QUESTION:

Which of the following are functions of Mitochondria?

1. Regulates the metabolic activity of the cell

2. Promotes the growth of new cells and cell multiplication

3. Carrying and transmitting hereditary materials

Select the correct answer using the code given below:

(a) 1 and 2 only

(b) 2 and 3 only

(c) 3 only

(d) 1.2 and 3

Answer