Unique – XYY: Understanding Chromosome Disorders
Article Title: Unique – XYY
Authors: Unique – Rare Chromosome Disorder Support Group
Date of Publication: 2006
“Approximately 1 boy in 1000 has XYY chromosomes. In the cells of their body, instead of 46 chromosomes including one X and one Y chromosome, they have one X and two Y chromosomes, making 47 in all. The impact of the extra Y chromosome is extremely variable. The great majority of boys and men with an extra Y chromosome are never aware of it, because they do not have symptoms that lead to a diagnosis. Only a small fraction of boys and men with XYY are ever diagnosed: recent estimates suggest 2.5% in the United Kingdom and 20% in Denmark.