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CAR: Anomalies - Chromosome
YY Syndrome

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Introduction Antenatal Postnatal West Midlands Data


YY syndrome occurs as a result of one or more additional Y chromosomes. Affected males have karyotype 47XYY or 48XYYY rather than the typical 46XY.

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Cases of YY syndrome have no distinguishing features on ultrasound

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Many affected males are clinically undetected as this syndrome presents with only subtle features. Individuals have normal birthweights but exhibit increased growth in childhood resulting in tall statures with disproportionately long legs. Some individual may be affected by hypogonadism and infertility but most have normal genitals, hormone levels and fertility. Mean IQ is lower and some association with high aggression and compulsive behaviour have been reported.

Individuals with karyotypes 48XYYY have more pronounced mental retardation and tall stature.

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To be added

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© Perinatal Institute 2011