[DAX-1 abnormality].

DAX-1 is an orphan nuclear receptor that plays a key role in the development and function of the adrenal gland and hypothalamic-pituitary-gonadal axis. Absence of DAX-1 results in X-linked adrenal hypoplasia congenita, a human inherited disorder characterized by adrenal insufficiency and hypogonadotropic hypogonadism. The DAX-1 gene may be responsible for a male-to-female sex reversal syndrome, referred to as dosage sensitive sex reversal(DSS), due to the duplication of a small region of human chromosome Xp21. Dax-1 and Sry have been shown to act antagonistically in the mouse system, where over-expression of Dax-1 leads to female development and increasing activity of Sry to male development. Although these data strongly implicate Dax-1 in sex determination, there is no evidence that DAX-1 is equivalent to DSS in human.