XYY syndrome is characterized clinically by tall stature evident from childhood, macrocephaly, facial features (mild hypertelorism, low set ears, a mildly flat malar region), macrodontia, speech delay and an increased risk for social and emotional difficulties, attention deficit hyperactive disorder and autistic spectrum disorder, and a higher risk for criminal behavior.
47, XYY syndrome is a sex chromosome aneuploidy where males receive an additional Y chromosome.
