What If Our Body’s Power Station Goes Wrong? Gene Therapy May Help

The mitochondria are known as our body’s power station since it generates energy for our cellular activities, which is a crucial cellular organelle. The high-energy-required organs like the heart and brain need to function properly. However, the dysfunctions of mitochondria are hard to diagnose, increasing the difficulty in treatment. The wide variety of symptoms included developmental delay, movement disorders, blindness, metabolism diseases.  

A possible cure for mitochondrial diseases was proposed by the University of Cambridge on Cell. They edited the abnormal genomes in the rat, replacing DNA base C into T. It is considered to be one-off therapy for mitochondrial diseases in the future. 

What If Abnormality in mtDNA is Found? Gene Editing may be the Silver Lining 

The mitochondria have their DNA- even different from the rest of your body cells. Every cell has 1000 pairs of mitochondrial DNA(mtDNA). The damage and mutation ratio in the mtDNA may result in mitochondrial diseases. Generally, the symptoms will appear when there is over 60% of mtDNA mutated, with the prevalence rate at 1/5000. 

The University of Cambridge makes use of a cytosine double-stranded DNA deaminase (DddA) base editor, DdCBE, to erase the abnormality. They inject the DdCBE with the Adeno-Associated Virus(AAV) vector into the rat. The base editor is then absorbed into the animal body and recovers the abnormal mtDNA. 

DdCBE is the first genetic editor used in living things. However, DdCBE can only recover the mitochondrial DNA with partial genome deficiency. 

The Three-Person IVF, Another Hope on Preventing Mitochondrial Diseases, Still Has A Long Way to Success

Lots of scientists have concentrated on finding cures for mitochondrial diseases in recent years. The British government announced the draft bill on Mitochondrial Donation in 2014, which allowed the three-person In vitro fertilization (IVF) to apply. 

The three-person IVF prevents the baby from suffering the mitochondrial diseases by replacing the faulty mitochondria with normal mitochondria from the third person. The children thus will be created from three genetic parents- one is the sperm donor, one is the egg donor, and one is the mitochondrial donor. 

Although the bill may be the thread of hope, there are limitations on the technical aspect. Ethically speaking, the three-person IVF leads to the provoking issues of consumerized babies.  

The University of Cambridge edits mtDNA to a small extent in gene therapy, which will be the potential cure in the future. 

Author

GeneOnline Team