Causes of Congenital adrenal hyperplasia
Common Causes of Congenital adrenal hyperplasia
Following is a list of common causes of Congenital adrenal hyperplasia:
Congenital adrenal hyperplasia Causes: Book Excerpts
What causes Congenital adrenal hyperplasia?
Causes: Congenital adrenal hyperplasia:
The most common cause of CAH is a deficiency of the enzyme 21-hydroxylase. The gene for this enzyme lies on chromosome 6. There are two copies of the gene because of a duplication that occurred hundreds of thousands of years ago. One gene is called CYP21 and is the active gene; the other is called CYP21P and is inactive. The 21-hydroxylase deficiency is unique because most mutations result from the transfer of genetic information between inactive and active genes.
(Source: Genes and Disease by the National Center for Biotechnology)
Related information on causes of Congenital adrenal hyperplasia:
As with all medical conditions,
there may be many causal factors.
Further relevant information on causes of Congenital adrenal hyperplasia may be found in:
Causes of Congenital adrenal hyperplasia: Online Medical Books
16 MEDICAL BOOKS ONLINE!
Review excerpts from medical books online, free, without registration,
for more information about the causes of Congenital adrenal hyperplasia.
Hearing Loss – Congenital:
Differential Diagnosis
(In A Page: Pediatric Signs and Symptoms)
- Infections
–CMV: Most common intrauterine infection
causing hearing loss
–Bacterial meningitis
–Congenital rubella: Cataracts, cardiovascular
anomalies, retinitis, mental retardation
–Congenital syphilis
–Toxoplasmosis
–Lyme disease - Metabolic
–Hyperbilirubinemia (kernicterus): Consider phototherapy or exchange transfusion if serum bilirubin >20 mg/dL in newborn
–Hypercholesterolemia
-
Ototoxic medications
–Aminoglycoside, gentamicin often needed for perinatal sepsis; >5 days risks hearing loss
-
Temporal bone anomaly
–Middle ear anomaly (results in conductive
hearing loss)
–Perilymphatic fistula
–Dilated vestibular aqueduct (±Mondini
deformity)
–Michel cochlear aplasia
–Scheibe aplasia: Membranous aplasia; bony
labyrinth normal
-
Nonsyndromic hereditary congenital deafness (connexin 26 gene mutation is responsible for half of all genetic deafness)
-
Syndromic hereditary congenital deafness
–Waardenburg: Telecanthus, confluent eyebrow, colored irides, white forlock
–Usher: Retinitis pigmentosa (totally blind by second to third decade), ataxia, vestibular dysfunction
–Alport: Progressive nephritis and hearing loss
–Apert (acrocephalosyndactyly): Craniofacial dysostosis
–Crouzon (craniofacial dysostosis): Prognathic mandibile, small maxilla
–Jervell and Lange-Neilsen: Heart disease
(prolonged QT interval)
–Pendred: Euthyroid goiter
–Oto-palatal-digital: Cleft palate, stubby
clubbed digits
–Congential aural atresia
» READ BOOK EXCERPT ONLINE »
Source: In A Page: Pediatric Signs and Symptoms, 2007
Adrenal hypofunction:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
Adrenal hypofunction occurs when more than 90% of both adrenal glands are destroyed, an occurrence that typically results from an autoimmune process in which circulating antibodies react specifically against the adrenal tissue. Other causes include tuberculosis (once the chief cause; now responsible for less than 10% of adult cases), bilateral adrenalectomy, hemorrhage into the adrenal gland, neoplasms, and infections (acquired immunodeficiency syndrome, histoplasmosis, and cytomegalovirus). Rarely, a familial tendency to autoimmune disease predisposes the patient to adrenal hypofunction and other endocrinopathies.
Secondary adrenal hypofunction that results in glucocorticoid deficiency can stem from hypopituitarism (causing decreased corticotropin secretion), abrupt withdrawal of long-term corticosteroid therapy (long-term exogenous corticosteroid stimulation suppresses pituitary corticotropin secretion and results in adrenal gland atrophy), or removal of a nonendocrine, corticotropin-secreting tumor. Adrenal crisis follows when trauma, surgery, or other physiologic stress exhausts the body’s stores of glucocorticoids in a person with adrenal hypofunction.
Adrenal hypofunction affects 1 in 16,000 neonates congenitally. In adults, it affects 8 in 100,000 people, and males and females are affected equally. There’s no racial predilection.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Adrenogenital syndrome:
Causes and incidence
(Professional Guide to Diseases (Eighth Edition))
CAH is transmitted as an autosomal recessive trait that causes deficiencies in the enzymes needed for adrenocortical secretion of cortisol and, possibly, aldosterone. Compensatory secretion of corticotropin produces varying degrees of adrenal hyperplasia. In simple virilizing CAH, deficiency of the enzyme 21-hydroxylase results in underproduction of cortisol. In turn, this cortisol deficiency stimulates increased secretion of corticotropin, producing large amounts of cortisol precursors and androgens that don’t require 21-hydroxylase for synthesis.
In salt-losing CAH, 21-hydroxylase is almost completely absent. Corticotropin secretion increases, causing excessive production of cortisol precursors, including salt-wasting compounds. However, plasma cortisol and aldosterone levels — both dependent on 21-hydroxylase — fall precipitously and, in combination with the excessive production of salt-wasting compounds, precipitate acute adrenal crisis. Corticotropin hypersecretion stimulates adrenal androgens, possibly even more than in simple virilizing CAH, and produces masculinization. Other rare CAH enzyme deficiencies exist and lead to increased or decreased production of affected hormones.
CAH is the most prevalent adrenal disorder in infants and children; simple virilizing CAH and salt-losing CAH are the most common forms. Acquired adrenal virilism is rare and affects twice as many females as males. About 1 in 10,000 to 18,000 are born with CAH.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Adenoid hyperplasia:
Causes
(Professional Guide to Diseases (Eighth Edition))
The cause of adenoid hyperplasia is unknown, but contributing factors may include heredity, chronic infection, chronic nasal congestion, persistent allergy, insufficient aeration, and inefficient nasal breathing. Inflammation resulting from repeated infection increases the patient’s risk of respiratory obstruction.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Adrenal hypofunction:
Causes
(Handbook of Diseases)
The following are causes of primary and secondary adrenal hypofunction and adrenal crisis.
Primary hypofunction
Addison’s disease occurs when more than 90% of both adrenal glands are destroyed. Such destruction usually results from an autoimmune process (autoimmune adrenalitis) in which circulating antibodies react specifically against the adrenal tissue.
CLINICAL TIP: Suspect adrenal insufficiency in patients with acquired immunodeficiency syndrome. Although symptoms may not be present, testing frequently reveals abnormal results.
Other causes include tuberculosis (once the chief cause; now responsible for less than 10% of adult cases), bilateral adrenalectomy, hemorrhage into the adrenal gland, neoplasms, and infections (histoplasmosis, cytomegalovirus). Rarely, a family history of autoimmune disease predisposes the patient to Addison’s disease and other endocrinopathies.
Secondary hypofunction
Secondary hypofunction, which results in glucocorticoid deficiency, can stem from hypopituitarism (causing decreased corticotropin secretion), abrupt withdrawal of long-term corticosteroid therapy (long-term exogenous corticosteroid stimulation suppresses pituitary corticotropin secretion and results in adrenal gland atrophy), or the removal of a corticotropin-secreting tumor.
Adrenal crisis
After trauma, surgery, or other physiologic stress, adrenal crisis exhausts the body’s stores of glucocorticoids in a person with adrenal hypofunction.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Cushing Syndrome (Adrenal Excess):
Cushing Syndrome - pathophysiology
(The 5-Minute Pediatric Consult)
- Cushing disease: Pituitary ACTH oversecretion, usually due to pituitary adenoma, with resultant bilateral adrenal hyperplasia
- Adrenal tumors
- Adrenal adenomas: Benign tumors that secrete mainly cortisol
- Adrenal cortical carcinomas: Usually large, rapidly growing tumors, which produce a variety of hormones including cortisol and androgens
- Ectopic ACTH production: A rare cause of Cushing syndrome in pediatrics. Small cell carcinoma, pheochromocytomas, medullary thyroid carcinoma, and carcinoid tumors can all secrete ectopic ACTH.
- Exogenous steroids: Iatrogenic Cushing syndrome is the most common cause in pediatrics. Cushing syndrome can be caused by chronic systemic, topical, or intranasal steroid, or ACTH use.
» READ BOOK EXCERPT ONLINE »
Source: The 5-Minute Pediatric Consult, 2008
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