Most people born with XYY syndrome have average intelligence but may experience developmental delays or learning disabilities.
This article discusses the symptoms, causes, diagnosis, and treatment of XYY syndrome.
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What Are the Symptoms of XYY Syndrome?
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Many boys and men with XYY syndrome have no significant or noticeable symptoms.
What Causes XYY Syndrome?
In rare cases, cell division errors can occur after conception and cause XYY syndrome.
This is known as 46,XY or 47,XYY mosaicism.
The exact cause of cell division errors is not fully understood.
How Is XYY Syndrome Diagnosed?
A healthcare provider can diagnose XYY syndrome before birth (prenatally) or after birth (postnatally).
However, up to 90% of people with XYY syndrome are never diagnosed.
Prenatal Testing
Some prenatalscreening testsfor genetic and chromosomal disorders can detect XYY syndrome during pregnancy.
The most common test that detects chromosomal disorders isnoninvasive prenatal testing (NIPT).
Postnatal Testing
After birth, a healthcare provider can diagnose XYY syndrome through a karyotype genetic test.
Akaryotype testanalyzes the size, shape, and number of chromosomes in some of the body’s cells.
Karyotype testing may involve:
The blood or cheek swab is sent to the lab for analysis.
In males with XYY syndrome, cells will contain XYY chromosomes rather than the usual XY.
Can You Treat XYY Syndrome?
There is no cure for XYY syndrome, so treatment focuses on addressing specific symptoms.
Early intervention and therapies support boys with XYY-associated learning disabilities, behavioral issues, or communication struggles.
Treatment options vary, depending on the age at diagnosis and symptom severity.
The increased risk ofpulmonary (lung)andneurologicalconditions, such asasthmaandseizuredisorders, may affect the shorter life span.
Most boys and men with XYY syndrome live full lives.
Some people born with the condition have physical characteristics and behavioral symptoms, while others do not.
XYY syndrome is associated with an increased risk of autism spectrum disorder and ADHD.
MedlinePlus.47,XYY syndrome.
Unique: Understanding Rare Chromosome and Gene Disorders.XYY.
National Organization for Rare Disorders.XYY syndrome.
Association for X and Y Chromosome Variations.About 47, XYY.
Gravholt CF.Sex-chromosome abnormalities.Emery and Rimoins Principles and Practice of Medical Genetics.
