XX male syndrome

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XX male syndrome
Classification and external resources
Specialty Lua error in Module:Wikidata at line 446: attempt to index field 'wikibase' (a nil value).
ICD-10 (Q98.3)
OMIM 278850
Patient UK XX male syndrome
[[[d:Lua error in Module:Wikidata at line 863: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]]

XX male syndrome (also called de la Chapelle syndrome, for Albert de la Chapelle, who characterized it in 1972[1][2]) is a rare sex chromosomal disorder. Usually, it is caused by unequal crossing over between X and Y chromosomes during meiosis in the father, which results in the X chromosome containing the normally-male SRY gene. When this X combines with a normal X from the mother during fertilization, the result is an XX male.

This syndrome occurs in approximately four or five in 100,000 individuals, making it less common than Klinefelter syndrome.[3][4]

Presentation

Symptoms usually include small testes and subjects are invariably sterile. Individuals with this condition sometimes have feminine characteristics, with varying degrees of gynecomastia but with no intra-abdominal Müllerian tissue.[5] According to research at the University of Oklahoma health science centers, most XX males are not stereotypically feminine and are typical boys and men[5] although other reports suggest that facial hair growth is usually poor and libido is diminished, with notable exceptions.[6]

Clinical diagnosis

  • Standard XX karyotype in two tissues (with at least one, or both, containing the male SRY gene)
  • Male external genitalia, sometimes showing hypospadias
  • Two testes which may or may not have descended the inguinal canal. Most XX males have descended testes.
  • Absence of Müllerian tissue

Pathophysiology

Males typically have one X chromosome and one Y chromosome in each diploid cell of their bodies. Females typically have two X chromosomes. XX males have two X chromosomes, with one of them containing genetic material from the Y chromosome, making them phenotypically male; they are genetically female but otherwise appear to be male.

See also

External links

References

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  4. http://www.healthline.com/galecontent/xx-male-syndrome Healthline.com: XX Male Syndrome
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