XYY syndrome
47,XYY
Also known as: 47 XYY, Jacobs syndrome
47,XYY is an extra Y chromosome in a male. Most individuals have a typical phenotype, often with tall stature.
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What the notation means
47count,XYYsex chromosomes
- count
- total chromosome count (normal = 46)
- sex chromosomes
- sex chromosomes: one X + two Y
Clinical notes
47,XYY
An extra Y. Usually tall stature; typically normal fertility and intelligence within the normal range. Often incidental.