DAX1 (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1) is a nuclear receptor protein that in humans is encoded by the NR0B1 gene (nuclear receptor subfamily 0, group B, member 1). The NR0B1 gene is located on the short (p) arm of the X chromosome between positions 21.3 and 21.2, from base pair 30,082,120 to base pair 30,087,136.
This gene encodes a protein that lacks the normal DNA-binding domain contained in other nuclear receptors. The encoded protein acts as a dominant-negative regulator of transcription of other nuclear receptors including steroidogenic factor 1. This protein also functions as an anti-testis gene by acting antagonistically to SRY. Mutations in this gene result in both X-linked congenital adrenal hypoplasia and hypogonadotropic hypogonadism.