Gene Therapy: An End to Hemophilia

Summary

This script delves into the circulatory system's response to injury, highlighting the role of clotting factors in stopping bleeding. It explains hemophilia, a condition where the body struggles to produce these factors, leading to excessive bleeding. Hemophilia A, the most common form, is a sex-linked disorder affecting more males due to the gene's location on the X chromosome. Treatments include clotting factor infusions, but gene therapy offers a revolutionary, one-time solution. A breakthrough gene therapy using AAV to deliver clotting factor VIII has shown an 85% reduction in bleeding rates and allowed 96% of patients to live normal lives without ongoing injections, promising a future where hemophilia doesn't dictate one's life.

Takeaways

• 💓 **Blood Circulation**: The heart pumps around 2,000 liters of blood per day.
• 🔍 **Blood Composition**: Blood contains not only red blood cells but also white blood cells and clotting factors.
• 🏗️ **Clotting Process**: Clotting factors are microscopic but crucial for stopping bleeding, similar to bricks in repairing a building.
• 🩹 **Clot Formation**: In healthy individuals, clotting is efficient, minimizing blood loss after an injury.
• 🩸 **Hemophilia Challenge**: Hemophiliacs struggle with clotting due to a deficiency in clotting factors, leading to excessive bleeding.
• 🧬 **Genetic Link**: Hemophilia is a sex-linked disorder caused by a gene on the X chromosome, affecting more males than females.
• 🌐 **Hemophilia Types**: Hemophilia A is the most common, affecting the gene responsible for clotting factor VIII.
• 💉 **Traditional Treatment**: Treatment typically involves lifelong infusions of clotting factor concentrates.
• 🧬 **Gene Therapy**: A one-time gene therapy can provide a lifetime supply of clotting factors by inserting a functional gene into cells.
• 🌟 **Gene Therapy Advancement**: The Roctavian gene therapy uses AAV to deliver the gene for clotting factor VIII, significantly reducing bleeding rates.

Q & A

How much blood does the human heart pump per day?

The human heart pumps around 2,000 liters of blood per day.

What are the components of blood besides red blood cells?

Blood contains white blood cells and clotting factors, among other components.

What role do clotting factors play in the body?

Clotting factors are like the bricks needed to repair a broken building, ensuring that the worst part of falls is the pain, not the blood loss.

What is hemophilia and how does it affect the body?

Hemophilia is a condition where the body is unable to produce or 'buy' enough clotting factors, making clotting difficult and leading to excessive bleeding.

How is hemophilia linked to the X chromosome?

The hemophilia gene is located on the X chromosome, making it a sex-linked disorder that affects more males than females.

What is Hemophilia A and how does it affect the body?

Hemophilia A is the most common type, affecting the gene that produces clotting factor VIII. It is genetically recessive, and individuals with two hemophilia alleles experience the most severe bleeding.

How is the severity of hemophilia determined?

The severity of hemophilia is determined by the number of hemophilia alleles an individual has. Those with two alleles have the lowest clotting factor levels and the most severe bleeding.

What is the most common type of treatment for hemophilia?

The most common type of treatment involves infusing clotting factor concentrates, which must be administered throughout a person's entire life.

How does gene therapy work for treating hemophilia?

Gene therapy involves inserting a functional gene into cells to deliver functional clotting factors using gene carriers called vectors, which are derived from viruses but are harmless and strictly therapeutic.

Which cells are targeted in gene therapy for hemophilia?

In gene therapy, liver cells are targeted because clotting factors are produced by them. The virus recognizes and attaches to its receptors to deliver the gene.

What is the Roctavian gene therapy and how does it work?

Roctavian is a gene therapy to treat hemophilia A using AAV or Adeno-Associated virus, which holds the gene for clotting factor VIII. The virus is injected into the bloodstream and delivered to liver cells, allowing for the production of the missing clotting factors.

What were the results of the breakthrough study on Roctavian gene therapy?

In a study on a group of 134 male patients, Roctavian was able to reduce rates of bleeding by 85% even two years post therapy, and 96% of patients were able to live normal lives without requiring replacement factor injection treatment.