Gene therapy involves:

Human insulin is being commercially produced from a transgenic species of

Consult internet and find out how to make orally active protein pharmaceutical. What is the major problem to be encountered?

How is a permanent cure for $ADA$ deficiency possible?

Which of the following is/are correct about Adenosine Deaminase $(ADA)$ deficiency?
$I$. In the absence of adenosine deaminase enzyme,purine metabolism is disturbed and $T$-lymphocytes fail to function.
$II$. $ADA$ deficiency is caused by the deletion of the gene for $ADA$.
$III$. In some cases,it can be cured by bone marrow transplantation and enzyme replacement therapy. But in both approaches,the patients are not completely cured.
$IV$. For permanent cure,genes isolated from the bone marrow cells producing $ADA$ at early embryonic stages can be a possible cure.
Which of the above statements are correct?

An example of gene therapy is