XX male syndrome

XX male syndrome
XX male syndrome
Classification and external resources
ICD-10 (Q98.3)
OMIM 278850

XX male syndrome (also called de la Chapelle syndrome, for a researcher who characterized it in 1972[1]) 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.[2][3]



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.[4] According to research at the University of Oklahoma health science centers, most XX males are not stereotypically feminine and are typical boys and men[citation needed] although other reports suggest that facial hair growth is usually poor and libido is diminished, with notable exceptions.[4][5]

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


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


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • irritable male syndrome — n. Anger and irritableness in men caused by a sudden drop in testosterone levels, particularly when brought on by stress. Also: IMS. Example Citation: Feeling anxious? Irritable, too? Has the stamina that used to fuel days and burn up the nights… …   New words

  • Irritable Male Syndrome — The Irritable Male Syndrome (IMS) is a recently coined term for a set of symptoms thought to be caused by a drop in testosterone levels in male mammals. It is a striking feature in male seasonally breeding mammals associated with the end of the… …   Wikipedia

  • irritable male syndrome — n. condition when men who suffer from stress become bad tempered or nervous or angry or grouchy due to the unexpected decline in the level of the male sexual hormone (testosterone) …   English contemporary dictionary

  • male answer syndrome — n. The tendency for some men to answer a question even when they don t know the answer. Also: MAS. Example Citations: Try an experiment. Ask a male friend a question, something completely outside his sphere of expertise. Will you get an answer?… …   New words

  • Male-limited precocious puberty — Classification and external resources OMIM 176410 Male limited precocious puberty (also known as familial sexual precocity and gonadotropin independent testotoxicosis)[1] is a form of gonadotropin independent …   Wikipedia

  • Male infertility — Classification and external resources ICD 10 N46 ICD 9 606 …   Wikipedia

  • Male genital disease — Classification and external resources ICD 10 N40 N51 ICD 9 600 608 …   Wikipedia

  • Syndrome XYY — Syndrome 47,XYY Le syndrome 47,XYY est une anomalie chromosomique caractérisée par la présence anormale d un deuxième chromosome Y. Il s agit donc d une aneuploïdie. Cette anomalie se retrouve donc uniquement chez des personnes de sexe masculin… …   Wikipédia en Français

  • Male breast cancer — Classification and external resources ICD 10 C50 ICD 9 175 …   Wikipedia

  • Male bra — – also known as a compression bra, compression vest, Gynecomastia vest, Manssiere or Bro – refers to brassieres that are worn by men. Adolescent boys and middle aged men sometimes develop breasts[1][2] and the estimates of those with the… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.