Haemophilias: advances towards genetic engineering replacement therapy

Area of Science:

• Genetics
• Molecular Biology
• Gene Therapy

Background:

• Hemophilia A and B are X-linked recessive disorders primarily affecting males.
• Genes for factor VIII and factor IX are located on the X chromosome (Xq28 and Xq27.1).
• Factor VIII gene: 186 kb DNA, 9 kb exon, ~9 kb mRNA. Factor IX gene: 34 kb, 8 exons, 1.6 kb mRNA.

Purpose of the Study:

• To explore the potential of gene therapy for treating hemophilia A and B.
• To evaluate ex vivo and in vivo gene modification approaches.
• To assess the efficacy of viral vectors in preclinical models.

Main Methods:

• Gene therapy via ex vivo (isolated cells) or in vivo (target tissue) modification.
• Utilizing retroviral and adenovirus-based vectors for gene delivery.
• Testing in preclinical models such as mice and hemophilic dogs.

Main Results:

• Clinically relevant levels of human factor VIII achieved in animal models.
• Demonstrated feasibility of gene therapy for hemophilia treatment.
• Identified challenges in gene expression persistence and immunological responses.

Conclusions:

• Gene therapy holds significant potential for treating hemophilia A and B.
• Improved viral vectors have shown efficacy in preclinical studies.
• Further advancements are needed to optimize expression and minimize immune reactions before human clinical trials.