XYY syndrome, similar to Klinelfelter syndrome, only affects males, and is caused by an extra copy of chromosome Y.
The prevalence is estimated at 1 in 1,000 male births. XYY syndrome is not inherited and is not affected by advanced parental age. Life expectancy is normal.
Most frequent clinical findings in patients with 47, XYY syndrome:
The syndrome does not cause any unusual physical characteristics or medical problems and is only detected after a genetic analysis.
- A small percentage is diagnosed with autistic disorders which affect their communication and social interaction abilities.
- Normal appearance, usually with a tall stature
- Increased vulnerability (behavior and stress tolerance problems)
Orpha.net – The portal for rare diseases and orphan drugs