Syndrome Man XX

The syndrome man XX is characterized at a person of Caryotype XX, having a male Phénotype in addition.
This pathology is due to a Translocation Gène SRY of the Y towards the X.

Other names of the disease

  • Syndrome Of the Vault

Etiology

  • Translocation of the Gene SRY located at the level of the Locus p11.3 of the Chromosome Y towards the X
Gene SRY controls the factor of Différenciation testiculaire which is essential in the sexual differentiation of the primitive Gonade in Testicule.

Incidence & Prevalence

The prevalence is estimated at 1/20 000 birth of boys. It does not seem to have of population with different prevalence.

Description

In 1 case out of 5 there exists a Hypospadias with the birth, the other people express the disease after puberty by an insufficiency of development of the testicles, a Gynécomastie and a Azoospermie. The examination of these people will find sometimes a cryptorchidie. If there exists a sexual ambiguity with the birth, the newborn is often declared like a boy.
Il does not exist difficulty of training nor of abnormal behavior among these patients. They are slightly smaller than the average.

Diagnosis

Private clinic

  • Chromosomic chart standard XX
  • male Genitals with sometimes hypospadias
  • Two testicles
  • Absence of derived mullériens
  • Azoospermie

Biological

  • Rate of FSH and LH normal or slightly high
  • Rate of Testosterone low
  • low Response of testosterone to pharmacological stimulation by HCG

Histology

The Biopsy testiculaire watch an absence of germinal cell with a hyperplasy of the Cells of Leydig.

Genetics

In situ hybridization by fluorescence detects the presence of gene SRY on an X chromosome. In the event of failure, genic amplification can make it possible to detect gene. At 20% of men XX, one cannot detect gene.

Differential diagnosis

Is posed primarily with sexual ambiguities.

Treatment

The hormonothérapie by testosterone is essential to avoid the secondary disorders with the insufficiency of testosterone.

Transmission mode

The majority of men XX are translocations of novo .

The genetic Council

Sources

  • Online Mendelian Inheritance in Man, OMIM (TM). Johns Hopkins University, Baltimore, MANDELEVIUM. MIM Number: 278850 * GeneTests: Medical Genetics Information Resource (database online). Copyright, University off Washington, Seattle. 1993-2005 Man XX
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