21-hydroxylase deficiency overview: Difference between revisions

Jump to navigation Jump to search
 
(37 intermediate revisions by 5 users not shown)
Line 1: Line 1:
__NOTOC__
__NOTOC__
{{Congenital adrenal hyperplasia due to 21-hydroxylase deficiency}}
{{21-hydroxylase deficiency}}


{{CMG}}; '''Associate Editor-In-Chief:''' {{CZ}} {{AAM}}
{{CMG}}; '''Associate Editor-In-Chief:''' {{MJ}} {{AAM}}
==Overview==
==Overview==
'''Congenital adrenal hyperplasia due to [[21-hydroxylase]] deficiency''' ('''21-OH CAH''') also known as ('''CAH1''') accounts for about 95% of diagnosed cases of [[congenital adrenal hyperplasia]], and congenital adrenal hyperplasia in most contexts refers to '''21-hydroxylase deficiency'''.<ref name="pmid10857554">{{cite journal| author=White PC, Speiser PW| title=Congenital adrenal hyperplasia due to 21-hydroxylase deficiency. | journal=Endocr Rev | year= 2000 | volume= 21 | issue= 3 | pages= 245-91 | pmid=10857554 | doi=10.1210/edrv.21.3.0398 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10857554  }} </ref>
21-hydroxylase deficiency is the most common type of [[congenital adrenal hyperplasia]]. [[Congenital adrenal hyperplasia]] was first discovered by Luigi De Crecchio, an Italian [[pathologist]] in 1865. Gene responsible for 21-hydroxylase deficiency is [[CYP21A1|CYP21A]]. This disease may be classified into two subtypes: classic and non-classic forms. In patients with 21-hydroxylase deficiency, there is a defective conversion of [[17-Hydroxyprogesterone|17-hydroxyprogesterone]] to 11-[[deoxycortisol]] which results in decreased [[cortisol]] synthesis and therefore increased [[corticotropin]] ([[ACTH]]) secretion. Symptom of 21-hydroxylase deficiency ranges from severe to mild or asymptomatic forms, depending on the degree of 21-hydroxylase enzyme deficiency. In classic type, main symptoms can be severe [[hypotension]] due to [[adrenal crisis]], [[ambiguous genitalia]] in females, and no symptoms or larger [[Phallus (genus)|phallus]] in males. In non-classic types, infants and male patients may have no symptoms and females may show [[virilization]] symptoms after [[puberty]]. [[17-Hydroxyprogesterone|17-hydroxyprogesterone]] level and [[cosyntropin]] stimulation test can be used to diagnosis. Medical therapy for classic type of 21-hydroxylase deficiency includes maternal administration of [[dexamethasone]], for [[genetically]] diagnosed intranatal patients; also [[hydrocortisone]] and [[fludrocortisone]] may be used in children and adults. Treatment for non-classic type of 21-hydroxylase deficiency in children includes [[hydrocortisone]] until [[puberty]] and in women [[oral contraceptive pills]] for regulating [[menstrual cycle]].
Congenital adrenal hyperplasia was first discovered by Luigi De Crecchio, an Italian anatomist. Congenital adrenal hyperplasia due to 21-hydorxylase deficiency is caused by mutations in the ''CYP21A2'' gene. The incidence of congenital adrenal hyperplasia due to 21-hydorxylase deficiency is approximately 7.1 per 100,000 individuals. The [[prevalence]] of congenital adrenal hyperplasia due to 21-hydroxylase deficiency ranges between 6.6 to 7.6 per 100,000 individuals. Ashkenazi Jews, Mediterranean individuals (e.g. Greek/Italians) may have higher prevalence than other population, the prevalence will be as high as 1:3 individuals.<ref name="pmid3259306">{{cite journal| author=Pang SY, Wallace MA, Hofman L, Thuline HC, Dorche C, Lyon IC et al.| title=Worldwide experience in newborn screening for classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency. | journal=Pediatrics | year= 1988 | volume= 81 | issue= 6 | pages= 866-74 | pmid=3259306 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3259306}} </ref> Congenital adrenal hyperplasia due to 21-hydorxylase deficiency must be differentiated from other causes of adrenal hyperplasia such as 11-β hydroxylase deficiency and 17-α hydroxylase deficiency. Symptoms of congenital adrenal hyperplasia due to 21-hydorxylase deficiency include [[dehydration]], [[vomiting]], and [[weight loss]]. Late symptoms include [[virilization]] and [[infertility]].
The mainstay of therapy for congenital adrenal hyperplasia due to 21-hydorxylase deficiency is [[glucocorticoid]] replacement.


==Historical Perspective==
==Historical Perspective==
[[Congenital adrenal hyperplasia]] was first discovered by Luigi De Crecchio, an Italian anatomist.
[[Congenital adrenal hyperplasia]] was first discovered by Luigi De Crecchio, an Italian [[pathologist]] in 1865. Explanation of hormonal aspects and [[Molecular|molecular characteristics]] remained unclear until 1980. From 1980 scientists started to describe [[enzymes]] and molecular basis of 21-hydroxyase deficiency.
==Classification==
==Classification==
Congenital adrenal hyperplasia due to 21-hydroxylase deficiency may be classified into several subtypes based on severity, time of onset, and the presence of [[virilization]].
21-hydroxylase deficiency may be classified into two types based on severity and time of onset: classic and non-classic forms. Classic form includes two subtypes salt-wasting and non-salt wasting 21-hydroxylase deficiency.
==Pathophysiology==
==Pathophysiology==
Development of congenital adrenal [[hyperplasia]] due to 21-hydroxylase deficiency is the result of a defective [[P450]]c21 enzyme.
In patients with 21-hydroxylase deficiency, there is a defective conversion of [[17-hydroxyprogesterone]] to 11-[[deoxycortisol]] which results in decreased [[cortisol]] synthesis and therefore increased [[corticotropin]] ([[ACTH|ACTH)]] secretion. The resulting [[adrenal]] stimulation leads to increased production of [[androgens]]. More than 95% of all cases of [[Congenital adrenal hyperplasia|CAH]] are caused by 21-hydroxylase deficiency. The clinical manifestation of [[congenital adrenal hyperplasia]] is closely related to the type and severity of disease. The severity of disease relates to the [[mutation]] type which is causes [[enzyme]] inactivity or hypo activity. There is a lack of [[enzyme]] in classic type of 21-hydroxylase deficiency; while in the non-classic form, enzymatic activity is reduced but sufficient to maintain normal [[glucocorticoid]] and [[mineralocorticoid]] production. Responsible gene for 21-hydroxylase deficiency is [[CYP21A1|CYP21A]]. This gene is located within the [[Human leukocyte antigen|human leucocyte antigen]] class III region of [[chromosome 6]]. Meiotic [[recombination]] events occurs in this genomic region as a result of the high degree of [[sequence homology]] between [[CYP21A2]] and its [[pseudogene]] [[CYP21A1]]. Approximately 70% of [[CYP21A2]] disease is due to [[gene conversion]] and [[Microdeletion|micro-deletions]] in [[CYP21A1]] [[gene]].


==Causes==
==Causes==
Congenital adrenal hyperplasia due to 21-hydroxylase deficiency is caused by mutations in the ''CYP21A2'' gene.
Causes of 21-hydroxylase deficiency include [[mutations]] in [[CYP21A1]] and [[CYP21A2]] gene on [[Chromosome 6|chromosome 6.]] Approximately 70% of [[CYP21A2]] disease is due to [[gene conversion]] and [[Microdeletion|microdeletions]] in [[CYP21A1]] [[gene]]; around 25% to 30% are chimeric [[genes]] due to large [[Deletion (genetics)|deletions]]. Less common causes are due to [[De novo mutation|de novo]] [[mutations]] because of high variability of the [[CYP21A2]] [[locus]]. Also [[chromosome 6]] [[uniparental disomy]] is rare cause of 21-hydroxylase deficiency with an unknown prevalence.
==Differentiating Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency from other Diseases==
==Differentiating Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency from other Diseases==
[[Congenital adrenal hyperplasia]] due to 21-hydroxylase deficiency must be differentiated from other adrenal diseases such as [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency|11-β hydroxylase deficiency]] and [[Congenital adrenal hyperplasia due to 17 alpha-hydroxylase deficiency|17-α hydroxylase deficiency]].
21-hydroxylase deficiency must be differentiated from [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency|11-β hydroxylase deficiency]], [[Congenital adrenal hyperplasia due to 17 alpha-hydroxylase deficiency|17-α hydroxylase deficiency]], [[androgen insensitivity syndrome]], 3β-Hydroxysteroid Dehydrogenase, [[polycystic ovarian syndrome]], [[hyperprolactinemia]], [[cushing syndrome]], and [[adrenal tumor]].


==Epidemiology and Demographics==
==Epidemiology and Demographics==
The incidence of congenital adrenal hyperplasia due to 21-hydroxylase deficiency is approximately 7.1 per 100,000 births. The [[prevalence]] of congenital adrenal hyperplasia due to 21-hydroxylate deficiency ranges between 6.6 to 7.6 per 100,000 individuals. Ashkenazi Jews, Mediterranean individuals (e.g. Greek/Italians) may have higher prevalence than other population, the prevalence will be as high as 1:3 individuals.
Worldwide, the [[incidence]] of 21-hydroxilase deficiency, classic salt wasting type is 5 per 100,000 persons. [[Prevalence]] varies according to ethnicity and geographic area; ranges from a low of 3.57 per 100,000 persons in Chinese population  to a high of  per 100,000 persons with an average [[prevalence]] of 357 per 100,000 persons in Yupik Eskimos in Alaska. This disease usually affects individuals of the Ashkenazi Jews and Mediterranean race. The classic type affects approximately 6.25 in 100,000 live births. Non-classic type is one of the most common [[autosomal recessive]] disorders in humans and affects approximately 100 in 100,000 individuals, but in up to 1–2% among [[inbred]] populations, such as Eastern European (Ashkenazi) Jews. [[Incidence]] for 21-hydroxylase deficiency is more prevalent in some ethnic groups, particularly in remote geographic regions such as Alaskan Yupiks. The non-classic form is one of the most common [[autosomal recessive]] diseases. The [[prevalence]] of the non-classic form may differ from 100 in 100,000 to 1000 in 100,000, with a higher [[prevalence]] among Mediterraneans, Hispanics, and Eastern European Jews.
<ref name="pmid3259306">{{cite journal| author=Pang SY, Wallace MA, Hofman L, Thuline HC, Dorche C, Lyon IC et al.| title=Worldwide experience in newborn screening for classical congenital adrenal hyperplasia due to 21-hydroxylase deficiency. | journal=Pediatrics | year= 1988 | volume= 81 | issue= 6 | pages= 866-74 | pmid=3259306 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3259306  }} </ref>
 
==Risk Factors==
==Risk Factors==
Presence of family history of congenital adrenal hyperplasia due to 21-hydroxylase deficiency is one of the most potent risk factors in disease development.
The most potent [[risk factors]] in the development of 21-hydroxylase deficiency is presence of [[family history]] of 21-hydroxylase deficiency, and being in certain [[Ethnic group|ethnic groups]], particularly Ashkenazi Jews and Yugoslavians and Yupik Inuits.


==Screening==
==Screening==
According to the the Endocrine Society’s CGS and Clinical Affairs Core Committee, screening for [[congenital adrenal hyperplasia]] due to 21-hydroxylase deficiency by determining the serum level of [[17-hydroxyprogesterone|17OHP]], [[androstenedione]], and [[cortisol]] is recommended in [[newborns]].<ref name="Wikipeadia"> https://en.wikipedia.org/wiki/Congenital_adrenal_hyperplasia_due_to_21-hydroxylase_deficiency#Newborn_screening</ref><ref name="pmid19390483">{{cite journal| author=Schwarz E, Liu A, Randall H, Haslip C, Keune F, Murray M et al.| title=Use of steroid profiling by UPLC-MS/MS as a second tier test in newborn screening for congenital adrenal hyperplasia: the Utah experience. | journal=Pediatr Res | year= 2009 | volume= 66 | issue= 2 | pages= 230-5 | pmid=19390483 | doi=10.1203/PDR.0b013e3181aa3777 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19390483  }} </ref>
According to Endocrine Society Clinical Practice Guideline, screening for 21-hydroxylase deficiency by measuring [[17-Hydroxyprogesterone|17-hydroxyprogesterone]] is recommended for all newborns. The Endocrine Society's Clinical Practice Guideline recommends that [[genetic counseling]] be provided for individuals who are planning to [[Conceive a child|conceive]], and there is a [[family history]] of 21-hydroxylase deficiency.


==Natural History, Complications and Prognosis==
==Natural History, Complications and Prognosis==
Common complications of  21-hydroxylase deficient congenital adrenal hyperplasia include [[short stature]], [[adrenal crisis]], [[infertility]], and [[precocious puberty]]. The prognosis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency is generally good with treatment.
If left untreated, patients with 21-hydroxylase deficiency may progress to develop [[complications]]. Common [[complications]] of  [[21-Hydroxylase|21-hydroxylase]] deficient [[congenital adrenal hyperplasia]] include [[short stature]], [[adrenal crisis]], [[infertility]], and [[precocious puberty]]. The [[prognosis]] of to 21-hydroxylase deficiency is generally good with treatment.


==Diagnosis==
==Diagnosis==
===History and Symptoms===
===History and Symptoms===
Symptoms of congenital adrenal hyperplasia due to 21-hydroxylase deficiency include [[dehydration]], [[vomiting]], and [[weight loss]]. Late symptoms include [[virilization]] and [[infertility]].
Symptom of 21-hydroxylase deficiency ranges from severe to mild or asymptomatic forms, depending on the degree of [[21-Hydroxylase|21-hydroxylase]] enzyme deficiency. There are three main clinical phenotypes: classic salt-wasting, classic non-salt-wasting (simple [[virilizing]]), and non-classic (late-onset). In classical type, main symptoms can be sever [[hypotension]] due to [[adrenal crisis]], [[ambiguous genitalia]] in females, and no symptoms or larger [[Phallus (genus)|phallus]] in males. In non-classic types, infants and male patients may have no symptoms and females may show [[virilization]] symptoms after [[puberty]].


===Physical Examination===
===Physical Examination===
Patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency usually appears [[underweight]] and [[dehydrated]]. Physical examination of patients with 21-hydroxylase deficient congenital adrenal hyperplasia is usually remarkable for [[hypotension]] and [[virilization]].
Patients with 21-hydroxylase deficiency usually appear [[underweight]] and [[dehydrated]]. Physical examination is usually remarkable for [[hypotension]] and [[virilization]].


===Laboratory Findings===
===Laboratory Findings===
Laboratory findings consistent with the diagnosis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency include [[hyponatremia]], [[hyperkalemia]], and low [[cortisol level]].
Laboratory findings consistent with the diagnosis of 21-hydroxylase deficiency differs in each disease type. [[17-hydroxyprogesterone]] level and [[Cosyntropin|cosintropin]] stimulation test can be used to diagnosis.
===Ultrasound===
===Ultrasound===
On [[ultrasound]], congenital adrenal hyperplasia due to 21-hydroxylase deficiency is characterized by enlarged, wrinkled surface, cerebriform adrenal glands.<ref name="Radiopeadia"> http://radiopaedia.org/articles/congenital-adrenal-hyperplasia</ref>
On [[ultrasound]], 21-hydroxylase deficiency is characterized by enlarged, wrinkled, and cerebriform [[adrenal glands]]. Also [[testicular masses]] may be seen in the setting of classic disease.
 
===CT Scan===
===CT Scan===
On [[CT scan]], congenital adrenal hyperplsia due to 21-hydroxylase deficiency is characterized by bilateral symmetric enlargement of [[adrenal glands]].
On abdominal [[CT scan]], 21-hydroxylase deficiency is characterized by bilateral symmetric enlargement of the [[adrenal glands]].


===MRI===
===MRI===
On [[MRI]], congenital adrenal hyperplsia due to 21-hydroxylase deficiency is characterized by bilateral symmetric enlargement of [[adrenal glands]].
On abdominal [[MRI]], 21-hydroxylase deficiency is characterized by bilateral symmetric enlargement of the [[adrenal glands]].
 
===Other Diagnostic Studies===
 
Immunohistochemical staining of the adrenal-gland may be used for the diagnosis of congenital adrenal hyperplasia due to 21-hydroxylase deficiency and it shows [[hyperplasia]], poorly defined zonation, and intermingling of the [[chromaffin]] and cortical cells.


==Treatment==
==Treatment==
===Medical Therapy===
===Medical Therapy===
The mainstay of therapy for congenital adrenal hyperplasia due 21-hydroxylase deficiency is [[glucocorticoid]] replacement.
Medical therapy for classic type of 21-hydroxylase deficiency includes maternal administration of [[dexamethasone]], for [[genetically]] diagnosed intranatal patients, and [[hydrocortisone]] and [[fludrocortisone]] in may be used in children and adults. Treatment for non-classic type of 21-hydroxylase deficiency in children includes [[hydrocortisone]] until [[puberty]] and in women [[oral contraceptive pills]] for regulating [[menstrual cycle]]. Men with non-classic type of 21-hydroxylase deficiency are asymptomatic and they do not need treatment.


===Surgery===
===Surgery===
[[Surgery]] is not the first-line treatment option for patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Surgical reconstruction of abnormal genitalia is usually reserved for severely [[virilization|virilized]] girls.
[[Surgery]] is not the first-line treatment option for patients with 21-hydroxylase deficiency. Surgical reconstruction of abnormal [[genitalia]] is usually reserved for severely [[virilization|virilized]] girls.
===Primary Prevention===
===Primary Prevention===
There are no primary preventive measures available for congenital adrenal hyperplasia due to 21-hydroxylase deficiency.
There are no primary preventive measures available for 21-hydroxylase deficiency.
===Secondary Prevention===
===Secondary Prevention===
Continued monitoring of hormone balance and careful readjustment of [[glucocorticoid]] dose is helpful in controlling [[fertility]] and preventing [[adrenal crisis]].
Continued monitoring of hormone balance and careful readjustment of [[glucocorticoid]] dose is helpful in controlling [[fertility]] and preventing [[adrenal crisis]] in patient with 21-hydroxylase deficiency.
 
==References==
==References==
{{Reflist|2}}
{{Reflist|2}}
[[Category:Disease]]
[[Category:Disease]]
[[Category:Pediatrics]]
[[Category:Pediatrics]]
Line 71: Line 66:
[[Category:Genetic disorders]]
[[Category:Genetic disorders]]
[[Category:Intersexuality]]
[[Category:Intersexuality]]
[[Category:Medicine]]
[[Category: Up-To-Date]]
{{WikiDoc Help Menu}}
{{WikiDoc Help Menu}}
{{WikiDoc Sources}}
{{WikiDoc Sources}}

Latest revision as of 15:27, 24 July 2020

Congenital adrenal hyperplasia main page

21-hydroxylase deficiency Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating 21-Hydroxylase Deficiency from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

X Ray

CT

MRI

Ultrasound

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

21-hydroxylase deficiency overview On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of 21-hydroxylase deficiency overview

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on 21-hydroxylase deficiency overview

CDC on 21-hydroxylase deficiency overview

21-hydroxylase deficiency overview in the news

Blogs on 21-hydroxylase deficiency overview

Directions to Hospitals Treating 21-Hydroxylase Deficiency

Risk calculators and risk factors for 21-hydroxylase deficiency overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Mehrian Jafarizade, M.D [2] Ahmad Al Maradni, M.D. [3]

Overview

21-hydroxylase deficiency is the most common type of congenital adrenal hyperplasia. Congenital adrenal hyperplasia was first discovered by Luigi De Crecchio, an Italian pathologist in 1865. Gene responsible for 21-hydroxylase deficiency is CYP21A. This disease may be classified into two subtypes: classic and non-classic forms. In patients with 21-hydroxylase deficiency, there is a defective conversion of 17-hydroxyprogesterone to 11-deoxycortisol which results in decreased cortisol synthesis and therefore increased corticotropin (ACTH) secretion. Symptom of 21-hydroxylase deficiency ranges from severe to mild or asymptomatic forms, depending on the degree of 21-hydroxylase enzyme deficiency. In classic type, main symptoms can be severe hypotension due to adrenal crisis, ambiguous genitalia in females, and no symptoms or larger phallus in males. In non-classic types, infants and male patients may have no symptoms and females may show virilization symptoms after puberty. 17-hydroxyprogesterone level and cosyntropin stimulation test can be used to diagnosis. Medical therapy for classic type of 21-hydroxylase deficiency includes maternal administration of dexamethasone, for genetically diagnosed intranatal patients; also hydrocortisone and fludrocortisone may be used in children and adults. Treatment for non-classic type of 21-hydroxylase deficiency in children includes hydrocortisone until puberty and in women oral contraceptive pills for regulating menstrual cycle.

Historical Perspective

Congenital adrenal hyperplasia was first discovered by Luigi De Crecchio, an Italian pathologist in 1865. Explanation of hormonal aspects and molecular characteristics remained unclear until 1980. From 1980 scientists started to describe enzymes and molecular basis of 21-hydroxyase deficiency.

Classification

21-hydroxylase deficiency may be classified into two types based on severity and time of onset: classic and non-classic forms. Classic form includes two subtypes salt-wasting and non-salt wasting 21-hydroxylase deficiency.

Pathophysiology

In patients with 21-hydroxylase deficiency, there is a defective conversion of 17-hydroxyprogesterone to 11-deoxycortisol which results in decreased cortisol synthesis and therefore increased corticotropin (ACTH) secretion. The resulting adrenal stimulation leads to increased production of androgens. More than 95% of all cases of CAH are caused by 21-hydroxylase deficiency. The clinical manifestation of congenital adrenal hyperplasia is closely related to the type and severity of disease. The severity of disease relates to the mutation type which is causes enzyme inactivity or hypo activity. There is a lack of enzyme in classic type of 21-hydroxylase deficiency; while in the non-classic form, enzymatic activity is reduced but sufficient to maintain normal glucocorticoid and mineralocorticoid production. Responsible gene for 21-hydroxylase deficiency is CYP21A. This gene is located within the human leucocyte antigen class III region of chromosome 6. Meiotic recombination events occurs in this genomic region as a result of the high degree of sequence homology between CYP21A2 and its pseudogene CYP21A1. Approximately 70% of CYP21A2 disease is due to gene conversion and micro-deletions in CYP21A1 gene.

Causes

Causes of 21-hydroxylase deficiency include mutations in CYP21A1 and CYP21A2 gene on chromosome 6. Approximately 70% of CYP21A2 disease is due to gene conversion and microdeletions in CYP21A1 gene; around 25% to 30% are chimeric genes due to large deletions. Less common causes are due to de novo mutations because of high variability of the CYP21A2 locus. Also chromosome 6 uniparental disomy is rare cause of 21-hydroxylase deficiency with an unknown prevalence.

Differentiating Congenital Adrenal Hyperplasia due to 21-Hydroxylase Deficiency from other Diseases

21-hydroxylase deficiency must be differentiated from 11-β hydroxylase deficiency, 17-α hydroxylase deficiency, androgen insensitivity syndrome, 3β-Hydroxysteroid Dehydrogenase, polycystic ovarian syndrome, hyperprolactinemia, cushing syndrome, and adrenal tumor.

Epidemiology and Demographics

Worldwide, the incidence of 21-hydroxilase deficiency, classic salt wasting type is 5 per 100,000 persons. Prevalence varies according to ethnicity and geographic area; ranges from a low of 3.57 per 100,000 persons in Chinese population  to a high of  per 100,000 persons with an average prevalence of 357 per 100,000 persons in Yupik Eskimos in Alaska. This disease usually affects individuals of the Ashkenazi Jews and Mediterranean race. The classic type affects approximately 6.25 in 100,000 live births. Non-classic type is one of the most common autosomal recessive disorders in humans and affects approximately 100 in 100,000 individuals, but in up to 1–2% among inbred populations, such as Eastern European (Ashkenazi) Jews. Incidence for 21-hydroxylase deficiency is more prevalent in some ethnic groups, particularly in remote geographic regions such as Alaskan Yupiks. The non-classic form is one of the most common autosomal recessive diseases. The prevalence of the non-classic form may differ from 100 in 100,000 to 1000 in 100,000, with a higher prevalence among Mediterraneans, Hispanics, and Eastern European Jews.

Risk Factors

The most potent risk factors in the development of 21-hydroxylase deficiency is presence of family history of 21-hydroxylase deficiency, and being in certain ethnic groups, particularly Ashkenazi Jews and Yugoslavians and Yupik Inuits.

Screening

According to Endocrine Society Clinical Practice Guideline, screening for 21-hydroxylase deficiency by measuring 17-hydroxyprogesterone is recommended for all newborns. The Endocrine Society's Clinical Practice Guideline recommends that genetic counseling be provided for individuals who are planning to conceive, and there is a family history of 21-hydroxylase deficiency.

Natural History, Complications and Prognosis

If left untreated, patients with 21-hydroxylase deficiency may progress to develop complications. Common complications of 21-hydroxylase deficient congenital adrenal hyperplasia include short stature, adrenal crisis, infertility, and precocious puberty. The prognosis of to 21-hydroxylase deficiency is generally good with treatment.

Diagnosis

History and Symptoms

Symptom of 21-hydroxylase deficiency ranges from severe to mild or asymptomatic forms, depending on the degree of 21-hydroxylase enzyme deficiency. There are three main clinical phenotypes: classic salt-wasting, classic non-salt-wasting (simple virilizing), and non-classic (late-onset). In classical type, main symptoms can be sever hypotension due to adrenal crisis, ambiguous genitalia in females, and no symptoms or larger phallus in males. In non-classic types, infants and male patients may have no symptoms and females may show virilization symptoms after puberty.

Physical Examination

Patients with 21-hydroxylase deficiency usually appear underweight and dehydrated. Physical examination is usually remarkable for hypotension and virilization.

Laboratory Findings

Laboratory findings consistent with the diagnosis of 21-hydroxylase deficiency differs in each disease type. 17-hydroxyprogesterone level and cosintropin stimulation test can be used to diagnosis.

Ultrasound

On ultrasound, 21-hydroxylase deficiency is characterized by enlarged, wrinkled, and cerebriform adrenal glands. Also testicular masses may be seen in the setting of classic disease.

CT Scan

On abdominal CT scan, 21-hydroxylase deficiency is characterized by bilateral symmetric enlargement of the adrenal glands.

MRI

On abdominal MRI, 21-hydroxylase deficiency is characterized by bilateral symmetric enlargement of the adrenal glands.

Treatment

Medical Therapy

Medical therapy for classic type of 21-hydroxylase deficiency includes maternal administration of dexamethasone, for genetically diagnosed intranatal patients, and hydrocortisone and fludrocortisone in may be used in children and adults. Treatment for non-classic type of 21-hydroxylase deficiency in children includes hydrocortisone until puberty and in women oral contraceptive pills for regulating menstrual cycle. Men with non-classic type of 21-hydroxylase deficiency are asymptomatic and they do not need treatment.

Surgery

Surgery is not the first-line treatment option for patients with 21-hydroxylase deficiency. Surgical reconstruction of abnormal genitalia is usually reserved for severely virilized girls.

Primary Prevention

There are no primary preventive measures available for 21-hydroxylase deficiency.

Secondary Prevention

Continued monitoring of hormone balance and careful readjustment of glucocorticoid dose is helpful in controlling fertility and preventing adrenal crisis in patient with 21-hydroxylase deficiency.

References


Template:WikiDoc Sources