Farrah Abraham Threatens Defamation Lawsuit Over DNA Necklace

Farrah Abraham is threatening to sue a company she claims told TMZ no one wants her DNA.

The woman who made backdoors more famous than ever fired off a letter to ZTPR, a public relations firm that reps a company that worked with Farrah to create necklaces with vials of her DNA.

Farrah cut a deal with the DNA company to sell the necklaces, and the lion's share of profits would go to a charity of her choice.

Now here's why she's threatening suit. TMZ got hold of a letter ZTPR sent to Farrah, informing her she was fired because she was more concerned with self-promotion than selling the necklaces. And the necklace thing was a big bust ... the letter says not a single person wanted Farrah's DNA.

So she sent ZTPR a letter -- which we also got -- accusing the company of leaking the termination letter to us and defaming her. Farrah's lawyer wrote, "My client has zero tolerance for defamation, as her reputation is her brand."

The lawyer says Farrah is "beyond perturbed" and wants $20,000 from ZTPR to make things right.