Need simple will give ! why can damage to a nucleic acid lead to a person not producing an enzyme?

Because the nucleic acid is damaged, so how is it going to produce anything without a miracle?

Nucleic acids are the main information-carrying molecules of the cell, and, by directing the process of protein synthesis, they determine the inherited characteristics of every living thing. 

So if that is damaged then, of course, you would be out of luck.

The answers is a nuclear changes