21-hydroxylase deficiency (also known as congenital adrenal hyperplasia)

An inherited disorder that affects the adrenal glands. These glands are located on top of the kidneys and produce a variety of hormones that regulate many essential functions in the body. Two of these hormones, cortisol and aldosterone, are produced from cholesterol through the activity of an enzyme called 21-hydroxylase. Cortisol has numerous functions such as maintaining blood sugar levels, protecting the body from stress, and suppressing inflammation. Aldosterone, sometimes called the salt-retaining hormone, acts on the kidneys to regulate the levels of salt and water in the body, which affects blood pressure. People with 21-hydroxylase deficiency have a shortage of the 21-hydroxylase enzyme, which impairs the conversion of cholesterol to cortisol and aldosterone. When the precursors of cortisol and aldosterone build up in the adrenal glands, they are converted to male sex hormones called androgens. Androgens are normally responsible for the appearance of secondary sex characteristics in males (virilization). Elevated levels of androgens can affect the growth and development of both males and females.