What is Congenital Adrenal Hyperplasia, CYP11B1-related?
Congenital adrenal hyperplasia (CAH) is a group of genetic disorders that affect the body's adrenal glands. The adrenal glands regulate essential functions in the body, including the production of several important hormones. CAH occurs when the adrenal glands are unable to produce these hormones properly, resulting in a hormone imbalance.
CAH, caused by harmful genetic changes (mutations) in a gene called CYP11B1, is the second-most-common type of CAH. CYP11B1 provides instructions to make 11-beta-hydroxylase. Another name for this disorder is 11-beta-hydroxylase-deficient CAH (11b-OHD CAH). When 11-beta-hydroxylase is impaired, the adrenal glands are unable to produce certain critical hormones. The body responds to this deficiency by producing an excess of male sex hormones (androgens). Collectively, the excess androgen production and hormone deficiencies lead to a variety of medical problems, which vary in severity depending on the form of CAH. There are two major forms of 11b-OHD CAH: classic and non-classic.
The classic form is the most severe type of 11b-OHD CAH. Female newborns often have external genitals that do not clearly appear either male or female (ambiguous genitalia), though the internal reproductive organs develop normally. Signs of early puberty and exaggerated development of male characteristics (virilization) can occur in both males and females with CAH. These symptoms may include rapid growth and development in early childhood, but shorter-than-average height in adulthood, abnormal menstruation cycles for females, excess facial hair for females, early facial-hair growth for males, severe acne, and infertility in both men and women. In addition, two out of three individuals with the classic form will develop high blood pressure (hypertension), sometimes at a very young age. Hypertension can result in significant medical complications if not treated.
The non-classic form is the less severe type of 11b-OHD CAH. Symptoms related to excess androgen production can first appear in childhood, adolescence, or adulthood. Individuals with the non-classic form are born with genitals that appear to be normal. Both males and females may still exhibit rapid growth in childhood and shorter-than-average height in adulthood. Additionally, girls may experience symptoms of virilization, abnormal menstruation, and infertility. The non-classic form does not typically cause hypertension. Some individuals with non-classic CAH experience such mild symptoms that they do not even know that they have this condition.
How common is Congenital Adrenal Hyperplasia, CYP11B1-related?
The exact incidence of 11b-OHD CAH in the population is unknown. Some studies estimate it to be approximately 1 in 100,000 births worldwide. The incidence of 11b-OHD CAH is more common among individuals of Moroccan Jewish descent and may also be more common in other individuals of Jewish descent from North Africa and the Middle East. 11b-OHD CAH accounts for up to 8% of all CAH cases, depending on ethnic background.
How is Congenital Adrenal Hyperplasia, CYP11B1-related treated?
Currently, there is no cure for CAH; however, treatments are available to address some of the associated symptoms. Patients benefit from taking hormone-replacement medications, which work to correct the hormonal imbalances caused by CAH. Most people with the classic form will need to take hormone medications throughout their life. Those with the less severe forms of CAH are sometimes able to stop taking these medications in adulthood and are typically treated with lower doses. Some individuals with non-classic CAH do not require treatment. A team of doctors, including one who specializes in hormone conditions (an endocrinologist), will need to monitor medication dosages and side effects and the growth and sexual development of patients who receive treatment. Additionally, high blood pressure may require treatment.
Newborn females with ambiguous genitalia may need surgery to correct the function and appearance of the external genitals. Surgery, if needed, is usually performed during infancy, but can be done later in life.
Treatments provided during pregnancy may reduce the degree of virilization in female fetuses. However, because the long-term safety of prenatal treatment is unknown, these therapies are considered experimental and are not recommended by professional guidelines.
What is the prognosis for an individual with Congenital Adrenal Hyperplasia, CYP11B1-related?
With early diagnosis and proper management, most individuals with 11b-OHD CAH will have a normal life expectancy. Rarely, uncontrolled hypertension can lead to early death. Problems with growth and development, infertility, ambiguous genitalia, and virilization are monitored by physicians on an ongoing basis.