Question

in short state the problems faced by gene therapy.....

Answer 1

here are still quite a few obstacles in the way of the use of gene therapy to treat or cure disease. In short, the challenges are having the correct disease, the correct delivery mechanism, and the correct immunology.

First, the correct disease. Gene therapy is limited by the types of diseases that can be treated with an insertion of a gene, either for a limited amount of time or for forever. The first example of successful gene therapy in humans is the use of an adenovirus vector to insert the gene for adenosine deaminase into patients with severe combined immunodeficiency (SCID). This was a good proof of concept precisely because the disease is 1) a well characterized disease with known molecular mechanism, 2) in a population of cells (T cells) that is constantly regenerating and growing, so could reasonably use the new DNA inserted (liable cells), and 3) the missing gene is a relatively small gene (which fits in the viral vector [I'll get to that in the second part of answer]) that does not have much in terms of post-translational modification, complex localization, interaction/regulated expression. Additionally, something as risky as gene therapy is warranted in this case as SCID is very morbid (requiring individuals to become bubble boys). Exceptional therapies require exceptional diseases. There are very few single gene diseases that fit this narrow window of opportunity and justify the tremendous risk and expense .

Secondly, the actual delivery mechanism would be the elephant in the room. There are a variety of methods (vectors) attempted by scientists or at least theoretically considered. In broad strokes, scientists have considered nonviral and viral vectors. Nonviral vectors, whether in a lipid solution or something else, have the limiting challenges of extremely poor efficacy (for good reason our body doesn't randomly take up DNA from the environment), transient (there are no good nonbiological ways to incorporate new DNA into our genome. If it isn't incorporated, it would be only transcribed in just the cells that it entered for a little while, and not work in the renewing progeny cells), and can be potentially carcinogenic (without a specialized way to incorporate DNA it can easily disrupt our natural DNA). We simply don't understand enough about biology and cannot manipulate it easily enough to use pure chemical means for gene therapy.

Answer 2

Hey mate ☺️

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Other challenges faced in the field of gene therapy include: Most gene therapies are short-lived meaning patients need to undergo multiple treatments. Therapeutic DNA needs to be functional in the long-term and the cells containing it need to be long-lived and stable if the therapy is going to provide a permanent cure.

Hope it works♥️✌️