Which protein production was successfully introduced in $E. coli$?

The genetic defect-adenosine deaminase $(ADA)$ deficiency may be cured permanently by

The first clinical gene therapy was given in $1990$ to a $4$-year-old girl for the treatment of which disease?

An example of gene therapy is .......

What does the conventional method of diagnosis include?

Correct chronological order of the steps occurring during gene therapy are
$I$. Lymphocytes are obtained from the patients
$II$. Lymphocytes are transferred to the culture dishes
$III$. Lymphocytes are transfected with the normal $ADA$ genes
$IV$. The transfected cells are returned to the patients
The chronological order should be