double Y syndrome

Last reviewed 01/2018

This is an example of sex chromosome anomaly.

The genotype of affected individuals is 47, XYY.

There is an incidence of about 1 in 800 male births.

Clinical features of individuals with this genotype include:

• males are tall, fertile
• it was hypothesised that males with this genotype had minor mental and psychiatric illness, and that there was a higher than average incidence of this genotype in tall criminals. These hypotheses are now being disputed