Talking to your doctors about congenital adrenal hyperplasia (CAH) can feel like you’re learning a new language. Appointment notes, lab test results, and online resources are filled with acronyms and technical terms, and it’s normal to feel overwhelmed.

The good news is that over time, these words will begin to feel familiar. Use this guide as a reference to help you get up to speed on the terms you’re likely to see. Learning the “language” of CAH can help you feel more confident talking with your endocrinologist and your care team.

CAH Basics

This section details words and acronyms that describe CAH itself, including different types of CAH and how they affect the body.

Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia includes a group of inherited conditions that affect the adrenal glands and how they make certain hormones.

Let’s break it down word by word:

• Congenital — This means it’s a condition that was present at birth.
• Adrenal — The adrenal glands are two small glands that sit atop the kidneys and produce hormones like cortisol, aldosterone, and androgens.
• Hyperplasia — This refers to the growth of an organ or tissue larger than usual due to an increased number of cells.

Thus, the name of the condition means that you’re born with it and that it causes your adrenal glands to grow larger than normal.

Types of Congenital Adrenal Hyperplasia

There are different subtypes of CAH that are caused by slightly different genes and involve different hormone changes and symptoms. The most common form of CAH is 21-hydroxylase deficiency (21-OHD), which accounts for 95 percent of cases. It’s due to a variant in the CYP21A2 gene.

Symptoms can vary significantly from person to person, including changes to both sex hormones and cortisol (stress hormone).

Other rare types of CAH include:

• 11-beta-hydroxylase deficiency — Caused by a variant in the CYP11B1 gene
• 17-alpha-hydroxylase deficiency — Caused by a variant in the CYP17A1 gene
• 3-beta-hydroxysteroid dehydrogenase deficiency — Caused by a variant in the HSD3B2 gene
• Congenital lipoid adrenal hyperplasia — Caused by a variant in the STAR gene
• P450 oxidoreductase deficiency — Caused by a variant in the POR gene

Classic Versus Nonclassic Congenital Adrenal Hyperplasia

The 21-OHD form of CAH can also be described by the signs and symptoms it causes in the body. These categories include:

• Classic CAH — A more severe form of CAH that’s usually diagnosed in newborn screening and that requires lifelong treatment
• Nonclassic CAH — A milder form of CAH that isn’t usually diagnosed until childhood or adulthood and may not be detected on newborn screening

Types of Classic Congenital Adrenal Hyperplasia

Within the classic CAH category, there are different subtypes:

• Salt-wasting CAH — A subtype found in 75 percent of people with classic CAH when the body can’t make enough aldosterone, leading to low sodium (salt) levels in the blood and possible dehydration
• Simple-virilizing CAH — A subtype found in 25 percent of people with classic CAH where cortisol is low, but aldosterone levels are usually fine

Conditions Related to CAH

CAH can also be associated with other conditions. According to StatPearls, males with CAH sometimes experience a testicular adrenal rest tumor (TART). This is a noncancerous growth made of adrenal-like tissue.

In females, CAH can be confused with polyendocrine metabolic ovarian syndrome (PMOS), a common condition involving hormone and metabolism issues. Both TARTs and PMOS can cause problems with fertility.

Hormones and the Hypothalamic-Pituitary-Adrenal Axis

CAH mainly affects the production of hormones. A hormone is a chemical messenger that travels through the bloodstream to regulate body functions. These are some key hormones related to CAH you’re likely to hear about:

• Cortisol — This hormone made by the adrenal gland helps regulate stress response, blood pressure, blood sugar, and metabolism. People with CAH often have low cortisol levels, which causes the adrenal tissue to overgrow as compensation.
• Aldosterone — This hormone from the adrenal gland helps control sodium and potassium levels and maintain blood pressure.
• Androgens — These hormones are involved in growth and development and relate to sex characteristics. In CAH, androgen levels may be higher than normal.
• ACTH (adrenocorticotropic hormone) — This hormone from the pituitary gland sends signals to the adrenal glands to make cortisol. In CAH, these levels are higher than normal because the adrenal gland doesn’t make enough cortisol.

Hormones are produced in glands. The adrenal gland makes cortisol, aldosterone, and androgens.

Another gland related to CAH is the pituitary gland. This is a small gland at the base of the brain that controls several hormone-producing glands, including the adrenal glands.

The brain and these two glands communicate through the hypothalamic-pituitary-adrenal axis (HPA axis). This term describes the communication system between the brain and adrenal glands that regulates stress hormones like cortisol.

Genetics and Inheritance Terms

CAH is an inherited disease, meaning it can be passed down from parents to children. Here are some genetics terms that may come up in test results or appointments:

• Autosomal recessive disorder — A condition (like CAH) in which a child must inherit one altered gene from each parent to have the condition
• Carrier — A person who has one copy of a gene change but doesn’t usually have symptoms
• Variant — A change to a gene that can affect how it works
• CYP21A2 gene — A gene whose variants cause 21-hydroxylase deficiency, the most common form of CAH
• Genetic testing — A way to look for changes in genes to confirm a diagnosis or carrier status

Lab Tests and Monitoring Terms

CAH management often involves regular blood tests. These abbreviations frequently appear in lab reports. Here’s what they mean:

• 17-hydroxyprogesterone (17-OHP) — A hormone that is increased in most people with 21-OHD, often used to screen and monitor CAH
• Androstenedione (A4) — An androgen that may be elevated in CAH and helps doctors assess hormone control
• Plasma renin activity — A blood test that shows how well aldosterone is working and whether salt balance is stable
• Electrolytes — Minerals in the blood, like sodium and potassium, that help regulate fluids and muscle function
• Newborn screening — A routine blood test done shortly after birth in the United States to check for certain conditions, including classic CAH
• Bone age — An X-ray of the hand and wrist to see how quickly bones are maturing

Treatment and Medication Terms

Treatment for CAH focuses on replacing missing hormones and keeping hormone levels balanced. Here are some words about CAH treatment that you might hear.

• Glucocorticoids — These are medications that replace cortisol, including hydrocortisone, prednisone, and dexamethasone. Hydrocortisone is often prescribed for children with CAH, while prednisone and dexamethasone are longer-acting and sometimes used in adolescents and adults.
• Mineralocorticoids — These are medications that replace aldosterone to help maintain sodium and blood pressure. Fludrocortisone is a mineralocorticoid often prescribed for people with the salt-wasting form of CAH.
• Stress dose — This extra glucocorticoid medication is taken during illness, injury, or surgery, when the body would typically make more cortisol.
• Adrenal crisis — This is a serious, sometimes life-threatening condition caused by very low cortisol levels, which can lead to low blood pressure and requires emergency treatment.
• Intramuscular injection (IM injection) — This is a shot given into muscle, sometimes used in emergencies to deliver hydrocortisone quickly.

When in Doubt, Ask Your Doctor

Your medical care team won’t expect you to remember everything. Medical language can be dense, and it’s always OK to ask questions, even if you’ve asked the same question before.

Here are some tips for better following conversations with your CAH specialist:

• Ask your provider to explain concepts in simpler terms.
• Ask them to write things down.
• Request reputable websites or printed materials for review at home.
• Bring a notebook or keep notes in your phone.
• Bring a family member or friend along to keep notes or ask questions. It’s hard to keep track of everything on your own.

Over time, these terms and abbreviations will start to become familiar. Understanding the language of CAH can help you feel more confident, more informed, and more prepared to partner with your healthcare team in managing the condition.

Join the Conversation

On CAHteam, people share their experiences with congenital adrenal hyperplasia, get advice, and find support from others who understand.

What other CAH medical abbreviations have you heard your doctor use? Let others know in the comments below.