Page "Androgen insensitivity syndrome" Paragraph 61

It is theoretically possible for certain mutant androgen receptors to function without androgens ; in vitro studies have demonstrated that a mutant androgen receptor protein can induce transcription in the absence of androgen if its steroid binding domain is deleted.

Conversely, the steroid-binding domain may act to repress the AR transactivation domain, perhaps due to the AR's unliganded conformation.