Congenital Adrenal Hyperplasia

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  • Topic: Adrenal cortex, Cortisol, Androgen
  • Pages : 7 (2061 words )
  • Download(s) : 74
  • Published : December 3, 2011
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Definition
Congenital adrenal hyperplasia can affect both boys and girls. People with congenital adrenal hyperplasia lack an enzyme needed by the adrenal gland to make the hormones cortisol and aldosterone. Without these hormones, the body produces more androgen, a type of male sex hormone. This causes male characteristics to appear early (or inappropriately). About 1 in 10,000 to 18,000 children are born with congenital adrenal hyperplasia.

Signs and Symptoms
Girls will usually have normal female reproductive organs (ovaries, uterus, and fallopian tubes). They may also have the following changes: * Abnormal menstrual periods
* Deep voice
* Early appearance of pubic and armpit hair
* Excessive hair growth and facial hair
* Failure to menstruate
* Genitals that look both male and female (ambiguous genitalia), often appearing more male than female Boys won't have any obvious problems at birth. However, they may appear to enter puberty as early as 2 - 3 years of age. Changes may include: * Deep voice

* Early appearance of pubic and armpit hair
* Early development of male characteristics
* Enlarged penis
* Small testes
* Well-developed muscles
Both boys and girls will be tall as children but much shorter than normal as adults. Some forms of congenital adrenal hyperplasia are more severe and cause adrenal crisis in the newborn due to a loss of salt. Newborns with these forms develop severe symptoms shortly after birth, including: * Cardiac arrhythmias

* Dehydration
* Electrolyte changes
* Vomiting
Pathophysiology
The clinical manifestations of each form of congenital adrenal hyperplasia are related to the degree of cortisol deficiency and/or the degree of aldosterone deficiency. In some cases, these manifestations reflect the accumulation of precursor adrenocortical hormones. When present in supraphysiologic concentrations, these precursors cause abnormalities such as virilization or hypertension. The phenotype depends on the degree or type of gene deletion or mutation and the resultant deficiency of the steroidogenic enzyme. The enzymes and corresponding genes are displayed in the image below.

Enzymes and genes involved in adrenal steroidogenesis.
Two copies of an abnormal gene are required for disease to occur, and not all mutations and partial deletions result in disease. The phenotype can vary from clinically inapparent disease (occult or cryptic adrenal hyperplasia) to a mild form of disease that is expressed in adolescence or adulthood (nonclassic adrenal hyperplasia) to severe disease that results in adrenal insufficiency in infancy with or without virilization and salt wasting (classic adrenal hyperplasia). The most common form of adrenal hyperplasia (due to a deficiency of 21-hydroxylase activity) is clinically divided into 3 phenotypes: salt wasting, simple virilizing, and nonclassic. CYP21A is the gene that codes for 21-hydroxylase, CYP11B1 codes for 11-beta-hydroxylase, and CYP17 codes for 17-alpha-hydroxylase. Many of the enzymes involved in cortisol and aldosterone syntheses are cytochrome P450 (CYP) proteins. Diagnostic Test

Tests to diagnose congenital adrenal hyperplasia include:
* Physical exam. Your child's doctor will examine your child and evaluate symptoms. If, based on these findings, the doctor suspects congenital adrenal hyperplasia, the next step is to confirm the diagnosis with blood and urine tests. * Blood and urine tests. Tests used to diagnose congenital adrenal hyperplasia measure levels of hormones manufactured by the adrenal glands — cortisol, aldosterone and androgens. A diagnosis can be made when there are abnormal levels of these hormones. In many states, doctors are required to conduct hormonal tests for congenital adrenal hyperplasia in newborns during the first few days of life. Blood is drawn with a heel prick of the newborn and analyzed. Prenatal testing

Doctors have the tools to screen and diagnose...
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