View source for Medicine:46,XX testicular disorders of sex development

{{Merge to|XX male syndrome|date=June 2019}}{{Infobox medical condition (new)
| name            = 46,XX testicular disorders of sex development
| synonyms        = De la Chapelle syndrome
| image           = Human karyotype (259 34) Karyotype Human 46,XX (woman).jpg
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| caption         = Human karyotype 46 XX
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'''46,XX testicular disorders of sex development''' (46,XX DSD) describes a condition in which individuals with two X [[Biology:Chromosome|chromosome]]s in each cell, the pattern typically found in females, have a male [[Biology:Phenotype|phenotype]] appearance.<ref>{{Cite web|url=http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=GB&Expert=393|title=Orphanet: 46,XX testicular disorder of sex development|last=RESERVED|first=INSERM US14 -- ALL RIGHTS|website=www.orpha.net|access-date=2017-01-12}}</ref><ref>{{cite journal|last1=Délot|first1=EC|last2=Vilain|first2=EJ|last3=Pagon|first3=RA|last4=Adam|first4=MP|last5=Ardinger|first5=HH|last6=Wallace|first6=SE|last7=Amemiya|first7=A|last8=Bean|first8=LJH|last9=Bird|first9=TD|last10=Fong|first10=CT|last11=Mefford|first11=HC|last12=Smith|first12=RJH|last13=Stephens|first13=K|title=Nonsyndromic 46,XX Testicular Disorders of Sex Development|date=1993|pmid=20301589|url=https://www.ncbi.nlm.nih.gov/books/NBK1416/|accessdate=12 January 2017|publisher=University of Washington, Seattle|journal=GeneReviews}}updated 2015</ref> 46,XX testicular disorders of sex development may also be named 46,XX sex reversal, nonsyndromic 46,XX testicular DSD, [[Medicine:XX male syndrome|XX male syndrome]], and XX sex reversal.<ref name=NIH/>

==Presentation==
People with 46,XX testicular DSD have male external genitalia. They generally have small testes and may also have abnormalities such as undescended testes (cryptorchidism) or the urethra opening on the underside of the penis ([[Medicine:Hypospadias|hypospadias]]). A small number of affected people have external genitalia that do not look clearly male or clearly female (ambiguous genitalia). Affected children are typically raised as males and are likely to have a male gender identity.<ref name=NIH/>

==Cause==
[[File:PBB Protein SRY image.jpg|thumb|140 px|SRY Protein]]
In about 80 percent of individuals with 46,XX testicular disorder of sex development, the condition results from an abnormal exchange of genetic material between chromosomes (translocation). This exchange occurs as a random event during the formation of sperm cells in the affected person's father. The translocation causes the SRY gene to be misplaced, almost always onto an X chromosome. If a fetus is conceived from a sperm cell with an X chromosome bearing the SRY gene, it will develop as a male despite not having a Y chromosome. This form of the condition is called SRY-positive 46,XX testicular disorder of sex development.<ref name=NIH/>

About 20 percent of those with 46 XX testicular disorder of sex development do not have the [[Biology:SRY gene|SRY gene]]. This form of the condition is called SRY-negative 46,XX testicular disorder of sex development. The cause of the disorder in these individuals is often unknown, although changes affecting other genes have been identified. Individuals with SRY-negative 46,XX testicular disorder of sex development are more likely to have ambiguous genitalia than are people with the SRY-positive form.<ref name=NIH/>

==Diagnosis==
Cytogenetic testing shows the presence of the 46,XX karyotype.<ref name="46XXGeneReview">{{cite journal |last1=Délot |first1=Emmanuèle C |last2=Vilain |first2=Eric J |title=Nonsyndromic 46,XX Testicular Disorders of Sex Development |journal=GeneReviews |date=2003 |url=https://www.ncbi.nlm.nih.gov/books/NBK1416/ |accessdate=6 December 2018}}</ref>

==Treatment==
[[File:Testosteron.svg|thumb|120 px|Testosterone]]
At puberty, most affected individuals require treatment with the male sex hormone [[Chemistry:Testosterone|testosterone]] to induce development of male secondary sex characteristics such as facial hair and deepening of the voice (masculinization). Hormone treatment can also help prevent breast enlargement (gynecomastia). Adults with this disorder are usually shorter than average for males and are unable to have children (infertile).<ref name=NIH>{{cite web | title = 46,XX testicular disorder of sex development - Genetics Home Reference | url = https://ghr.nlm.nih.gov/condition/46xx-testicular-disorder-of-sex-development | accessdate = 2017-01-08  }}{{PD-notice}}</ref>

==Epidemiology==
Approximately 1 in 20,000 individuals with a male appearance have 46,XX testicular disorder.<ref name=NIH/>

==See also==
*[[Medicine:XX male syndrome|XX male syndrome]]
*[[Medicine:Disorders of sex development|Disorders of sex development]]
*Intersex medical interventions

==References==
{{Reflist}}

==Further reading==
*{{cite web|title=Ambiguous Genitalia. Uncertain genetalia information. Patient {{!}} Patient|url=http://patient.info/doctor/ambiguous-genitalia|website=Patient|accessdate=12 January 2017}}

== External links ==
{{Medical resources
|  ICD10           = Q99.1 
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|  OMIM            = 278850 300833 400045
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|  MeSH            = D058531
|  GeneReviewsNBK  = 
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|  Orphanet        = 393
}}

{{Chromosomal abnormalities|state=collapsed}}

[[Category:Congenital disorders]]

{{Sourceattribution|46,XX testicular disorders of sex development|1}}