Understanding Mitochondrial Donation Treatment

Context (LM): At least eight babies have been born in the United Kingdom (UK) using Mitochondrial Donation Treatment (MDT) to prevent the inheritance of mitochondrial diseases.

About Mitochondrial Donation Treatment (MDT)

MDT, also known as Mitochondrial Replacement Therapy, is an advanced fertility technique aimed at preventing the transmission of mitochondrial genetic disorders from mother to child.
It is considered a three-parent baby technique, as it includes genetic material from the biological mother (nuclear DNA), the father (nuclear DNA), and a donor (healthy mitochondrial DNA).
The United Kingdom became the first country to formally regulate and approve MRT in 2015, followed by Australia in 2021.
Limitations of MRT: It cannot cure people with existing mitochondrial disease or prevent mitochondrial disease caused by a mutation in nuclear DNA.

The faulty mitochondria in the mother’s egg are replaced with healthy mitochondria from a donor.
The resulting embryo has 99.8% DNA from the biological parents and 0.1–0.2% mitochondrial DNA from the donor.
This helps prevent serious and often fatal disorders caused by mitochondrial dysfunction, such as Muscular dystrophy, Heart, liver, and brain disorders.

It is performed before fertilization and involves transferring the meiotic spindle apparatus, containing the mother’s chromosomes, into a donor egg that has had its own spindle removed.
The reconstructed egg is then fertilized with the father’s sperm, and the embryo is implanted into the mother’s uterus.

It is carried out after fertilization.
The pronuclei (containing nuclear DNA from the mother and father) are removed from a fertilized egg with defective mitochondria and inserted into a donor zygote that has healthy mitochondria and has had its own pronuclei removed.

Mitochondrial disease (or Mito) is a group of diseases that affect the mitochondria’s capacity to produce the energy that organs need to function properly.
There are two types of mitochondrial diseases:
- One is caused by faulty genes in the nuclear DNA, which comes from both parents.
- The other is caused by faulty genes in the mitochondrial DNA, which is passed down only from the mother.

Currently, there is no effective treatment for mitochondrial diseases, though the symptoms are treated to improve the patient’s quality of life.

Mitochondria are a type of membrane-bound organelle found in a cell’s cytoplasm, often nicknamed the “powerhouse” or “battery” of a cell due to their critical role in energy production.
While much of our DNA is stored in the cell nucleus, mitochondria are unique organelles in that their DNA is stored in a circular chromosome, which is inherited through the maternal line. This genetic material is essential for mitochondria to function properly.