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Dr. Andrew Rynne
Dr. Andrew Rynne

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Exp 50 years

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Article Home Adult and Senior Health XYY Chromosome Pattern

XYY Chromosome Pattern

XYY Chromosome pattern is an rare chromosomal abnormality that is affecting males characterized by an extra copy of Y Chromosome ( 47 XYY).


47 XYY Trisomy is also called

  • 47 XYY Karyotype
  • 47 XYY Syndrome
  • Polysomy Y
  • XYY Chromosome Pattern
  • YY syndrome
  • Jacob’s Syndrome                               

XYY Chromosome Pattern

XYY chromosome pattern is a disorder of male genetic sex chromosome number where instead of normal 46 XY pattern there is an extra Y chromosome making it 47 XYY. This Syndrome less often produces any unusual Physical features. And most of the males with this syndrome are sexually active and have become biological father of children.

Signs and symptoms

  • Tall stature
  • Severe Acne during adolescent
  • Thin personality
  • Learning Difficulties
  • Delayed speech and Language skills
  • Delayed motor developments
  • Antisocial or aggressive behavior 


XYY Syndrome is not an inherited disease. It is caused mainly by due to an abnormal cell division called Non-disjunction of the chromosome resulting in a sperm cell with an extra Y chromosome 24YY which on fusion with the ovum  23X  leads to 47XYY.

It is also seen as a Mosaic pattern with XY as XY/XY.

The XYY pattern of chromosome is also seen in a variant of Klinefelter’s Syndrome Variant XYY.