Gene Therapy — Prelims Strategy

Prelims Strategy

To effectively tackle NEET questions on gene therapy, a multi-pronged strategy focusing on conceptual clarity, specific examples, and critical distinctions is vital.

1
Master the Basics: — Start with a clear understanding of what gene therapy is, its goals (gene addition, silencing, correction), and the fundamental components (therapeutic gene, vector, target cells).
2
Know Your Vectors: — Memorize the key characteristics of the main viral vectors:

* Retroviruses: Integrate, long-term expression, only dividing cells, risk of insertional mutagenesis. * Adenoviruses: Episomal, transient expression, both dividing/non-dividing cells, strong immune response. * AAVs: Mostly episomal, both dividing/non-dividing cells, low immunogenicity, widely used. * Focus on their pros and cons, and which diseases they are typically used for.

1
Differentiate Approaches: — Clearly distinguish between:

* Ex vivo vs. In vivo: Understand where the modification takes place (outside vs. inside the body). * Somatic vs. Germline: This is critical. Remember that somatic therapy is non-heritable and clinically accepted, while germline therapy is heritable and ethically prohibited.

1
ADA-SCID is Key: — This is the most frequently tested example. Know that it's an ADA enzyme deficiency, treated by ex vivo gene therapy using a retroviral vector to introduce a functional ADA gene into lymphocytes/stem cells.
2
Ethical Considerations: — Be aware of the ethical debates surrounding germline gene therapy and the general safety concerns (immune response, insertional mutagenesis).
3
Practice MCQs: — Solve a variety of MCQs to identify common traps. For numerical problems (though rare in this topic), ensure you understand the underlying principle. For conceptual questions, break down each option and relate it back to your core knowledge. Pay attention to keywords like 'integrates,' 'episomal,' 'heritable,' 'ex vivo,' etc. Avoid rote memorization; instead, focus on understanding *why* a particular vector or approach is used for a specific condition.