High Quality Content by WIKIPEDIA articles! X-linked adrenal hypoplasia congenita is a genetic disorder that mainly affects males. It involves many endocrine tissues in the body, especially the adrenal glands. One of the main characteristics of this disorder is adrenal insufficiency, a reduction in adrenal gland function that results from incomplete development of the gland's outer layer (the adrenal cortex). Adrenal insufficiency typically begins in infancy or in childhood and can cause vomiting, difficulty with feeding, dehydration, extremely low blood sugar (hypoglycemia), and shock. However, adult-onset cases have also been described. Affected males may also lack male sex hormones, which leads to underdeveloped reproductive tissues, undescended testicles (cryptorchidism), delayed puberty, and an inability to father children (infertility).