NR0B1 encodes DAX-1, an orphan nuclear receptor that functions as a transcriptional corepressor lacking a DNA-binding domain 1. DAX-1 inhibits transcriptional activity of other nuclear receptors through heterodimeric interactions and is essential for hypothalamic-pituitary-adrenal-gonadal axis development 1. The protein can repress transcriptional activators through direct protein-protein interactions and bind DNA hairpin structures 2. Loss of NR0B1 function causes X-linked adrenal hypoplasia congenita (AHC), characterized by primary adrenal insufficiency presenting in infancy with salt-wasting and failure to thrive, followed by hypogonadotropic hypogonadism at puberty and impaired spermatogenesis 13. Clinical presentations are heterogeneous, including isolated mineralocorticoid insufficiency and precocious sexual development 34. NR0B1 mutations account for approximately 20% of congenital idiopathic hypogonadotropic hypogonadism cases 5. Duplication of the NR0B1 region causes dosage-sensitive sex reversal, with DAX-1 and the testis-determining factor Sry acting antagonistically in sex determination 2. Male patients carrying DAX-1 mutations frequently exhibit azoospermia, though assisted reproductive techniques may offer fertility options 6. Genetic testing is critical for accurate diagnosis and appropriate endocrine management.