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A tall adolescent male is referred for behavioral concerns and learning difficulties. Physical exam is unremarkable except for tall stature. Karyotype obtained during workup reveals 47,XYY.
- Karyotype: 47,XYY
- Paternal nondisjunction (meiosis II)
- Tall stature
- Normal fertility (usually)
- Learning difficulties (speech/language delays common)
- Behavioral issues in some (historically overstated)
- Normal physical exam (no distinctive dysmorphisms)
- Karyotype confirms 47,XYY and is diagnostic
- Often an incidental finding on prenatal cell-free DNA screening, chromosomal microarray, or a karyotype ordered for developmental or behavioral concerns
- Prenatal positive screens require confirmation by diagnostic testing (amniocentesis or CVS karyotype)
- Educational support as needed
- Supportive care