Congenital adrenal hyperplasia

Overview

Congenital adrenal hyperplasia (CAH) refers to a set of hereditary disorders that affect the adrenal glands. Each kidney has one adrenal gland on top of it. The adrenal glands produce vital hormones that the body requires to function properly.

With CAH, the adrenal glands are unable to produce one or more hormones because they lack a specific enzyme. Without this enzyme, the adrenal glands may not produce enough cortisol, aldosterone, or may produce too much androgen. Cortisol is a hormone that aids the body’s response to illness, injury, and stress. Aldosterone maintains proper salt and water levels in the body. While androgens initiate puberty and contribute significantly to normal growth and development. 

There are several forms of congenital adrenal hyperplasia. Two main types of CAHs make up 95% of all cases: 

• Classic CAH: It can result in severe adrenal problems such as shock and coma. It can be fatal if not detected and treated promptly. This is a more serious variant that is usually diagnosed at birth or early infancy. 
• Nonclassic CAH: It usually manifests signs or symptoms later in childhood, adolescence, or adulthood. Symptoms may not be noticeable. This is the milder form and more common form of CAH. 

The management strategy for CAH differs based on the particular subtype and the severity of its symptoms. While a complete cure for CAH is not currently available, addressing the symptoms can frequently be accomplished using medications and various therapeutic approaches. 

Symptoms

CAH can cause various symptoms. It usually differs depending on which gene has been compromised, the type of CAH, and the level of enzyme deficiency.

• Classic CAH: The signs and symptoms may include:
  • Inadequate cortisol production: Classic congenital adrenal hyperplasia (CAH) leads to an inadequate production of cortisol within the body. This can lead to difficulties in sustaining regular blood pressure, blood sugar, and energy levels, as well as complications during periods of physical stress, such as illness.
  • Adrenal crisis: This is a fatal condition characterized by a shortage of cortisol, aldosterone, or both. This condition can be fatal.
  • Atypical genitalia: Ambiguous genitalia in infants assigned female at birth means that the baby’s external sex organs mirror those of a typical boy, such as an enlarged clitoris that looks like a penis and partially closed labia that looks like a scrotum. However, the child still has typical female internal organs. The uterus, fallopian tubes, and ovaries develop normally. An enlarged penis in infants assigned male at birth is also common in classic CAH. 
  • Excess androgen: CAH causes the body to produce an excessive amount of androgens. Elevated androgen levels might cause symptoms associated with sexual hormones. Females with extra androgen hormones may develop facial hair, excessive body hair, and a deeper voice. Generally, it can result in low stature and early puberty in both boys and girls. This can include changes in voice, severe acne, and early pubic, armpit, and facial hair.
  • Altered growth: During childhood, there may be a period of accelerated growth characterized by a bone age that is advanced, potentially resulting in a final height that falls below the average range. 
  • Fertility issues: Infertility and abnormal menstrual periods may be caused by classic CAH.
• Nonclassic CAH: This is a milder type of CAH, and some may be completely unaware that they have this condition due to no symptoms. In this type of CAH, cortisol may be the only hormone lacking. The condition usually manifests itself in late childhood or early adulthood. 

Nonclassic CAH can manifest similarly in both males and females, with symptoms such as the premature development of pubic hair and other early signs of puberty, severe acne, and accelerated childhood growth accompanied by an advanced bone age, ultimately resulting in a shorter final height than anticipated.

At birth, females with nonclassic CAH might possess outwardly normal genitalia. Nevertheless, as they grow, they could experience the emergence of masculine traits like excessive facial and body hair growth, a deeper voice, and irregular or absent menstrual cycles. These changes might also lead to challenges in achieving pregnancy.

CAH can come to attention when male or female infants display signs of severe illness due to insufficient cortisol, aldosterone, or a combination of both. Classic CAH is commonly identified through routine newborn screening or when infants present with atypical genitalia. In the case of nonclassic CAH, children might display indications of early puberty. 

Parents who have concerns about CAH in their children can seek guidance from a healthcare professional for accurate diagnosis and appropriate treatment. Pregnant women with a heightened risk of CAH might receive a recommendation for genetic counseling.

Causes

CAH is occasionally known as 21–hydroxylase deficiency, as the insufficiency of the enzyme 21–hydroxylase is the primary underlying factor of CAH. This enzyme is essential for the production of adequate hormone levels within the body. In rare instances, CAH can result from the absence of another enzyme, known as 11–hydroxylase. 

CAH is an autosomal recessive condition. Every gene in the body has two copies, one from each parent. In your body, you inherit a pair of genes for each trait — one from your mother and one from your father. CAH develops when you receive mutated copies of the gene responsible for the deficiency from both of your parents.

Risk factors

Congenital adrenal hyperplasia can affect anyone. However, certain risk factors may increase one’s risk. This include having both parents affected by CAH or carrying the genetic change associated with the condition, as well as belonging to specific ancestral groups like Ashkenazi Jewish, Latino, Mediterranean, Yugoslav, or Yup’ik populations.