Biology – Genetic technology applied to medicine | e-Consult

Principles of Gene Therapy: Gene therapy aims to treat genetic diseases by introducing functional genetic material into a patient's cells. This can be achieved through several methods:

• Gene Addition: Introducing a functional copy of the mutated gene into the patient's cells. This is often done using a viral vector.
• Gene Inactivation: Inactivating a mutated gene to prevent it from producing a harmful protein.
• Gene Editing: Directly correcting the mutated gene within the patient's cells using tools like CRISPR-Cas9.

Treatment of SCID: SCID is caused by mutations in genes involved in T-cell development. Gene therapy can be used to treat SCID by:

• Identifying hematopoietic stem cells (HSCs) from the patient or a donor.
• Using a viral vector (often a retrovirus) to deliver a functional copy of the mutated gene into the HSCs.
• Infusing the modified HSCs back into the patient.
• The corrected HSCs then develop into functional T-cells, restoring immune function.

Treatment of Inherited Eye Diseases: Many inherited eye diseases, such as Leber congenital amaurosis (LCA), are caused by mutations in genes involved in retinal function. Gene therapy for these diseases typically involves:

• Using a viral vector to deliver a functional copy of the mutated gene directly into the retinal cells. This can be achieved through subretinal injection.
• The delivered gene then expresses the functional protein, potentially restoring or improving retinal function.

Gene therapy offers a potential cure for many genetic diseases, but challenges remain, including immune responses to the vector and the potential for insertional mutagenesis.