While XYY syndrome is typically associated with males, it is extremely rare but possible for individuals with a female phenotype to have a 46,XY/47,XYY mosaic condition.
Understanding XYY Syndrome
XYY syndrome is a genetic condition that occurs in males who are born with an extra Y chromosome. This results in a 47,XYY karyotype instead of the usual 46,XY. However, there are also cases where individuals can have a mosaic karyotype.
Mosaicism and Female Phenotype
Mosaicism refers to the presence of two or more genetically distinct cell lines in the same individual. A case was reported of a patient with a female phenotype who was diagnosed with a 46,XY/47,XYY mosaicism, where a portion of their cells had the typical male 46,XY karyotype and another portion of cells had the 47,XYY karyotype, instead of the typical 46,XX karyotype found in females. This means that while most of the cells might be contributing to a female phenotype, a subset of cells can carry the XYY genetic material.
Key Points
- Typical Presentation: XYY syndrome usually occurs in individuals with a male phenotype.
- Rarity in Females: It is exceedingly rare to find XYY mosaicism in individuals with a female phenotype.
- Mosaicism: The presence of a 46,XY/47,XYY mosaic karyotype can lead to atypical presentations.
| Characteristic | Typical XYY Syndrome | Female Phenotype with XYY Mosaicism |
|---|---|---|
| Typical Phenotype | Male | Female |
| Karyotype | 47,XYY | 46,XY/47,XYY Mosaic |
| Occurrence | More common | Extremely rare |
In conclusion, although highly unusual, girls can have the XYY genetic material through mosaicism. This makes it possible, though rare, for someone with a female phenotype to have the genetic makeup associated with XYY syndrome.
