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Double Y syndrome

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

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

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