What Is XYY Syndrome?
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Medically reviewed by Daniel Combs, MD
XYY syndrome (Jacobs syndrome or 47,XYY) is a genetic condition that occurs when a person assigned male at birth is born with an extra copy of the Y chromosome in some or all of their cells. Males are usually born with one X and one Y chromosome.
About 1 in 1,000 males are born with XYY syndrome and may have physical characteristics such as increased height, larger heads, and low muscle tone, though some have no noticeable signs or symptoms.
Most people born with XYY syndrome have average intelligence but may experience developmental delays or learning disabilities. XYY syndrome is associated with an increased risk of behavioral, social, and emotional challenges and conditions such as attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder.
This article discusses the symptoms, causes, diagnosis, and treatment of XYY syndrome.
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What Are the Symptoms of XYY Syndrome?Many boys and men with XYY syndrome have no significant or noticeable symptoms. When signs and symptoms of XYY syndrome occur, they can include a combination of physical and behavioral differences that vary from person to person.
Physical CharacteristicsBoys born with XYY syndrome may have some subtle physical characteristics associated with the condition, including the following:
Taller than average height
Hypotonia (low muscle tone)
Clinodactyly (curved pinky finger)
Hypertelorism (widely spaced eyes)
Cystic acne (during adolescence)
Delayed motor skills development, such as sitting and walking
Dental problems, such as baby teeth not falling out, overcrowded teeth, missing teeth, and poor tooth enamel
A forward-jutting jaw or an underbite
Some boys with XYY syndrome may have behavioral, emotional, learning, and social difficulties, such as:
Speech and language delays
Expressive language disorder
Learning disability (e.G., dyslexia)
Depression
Anxiety
Social skills impairment
Impulsivity
Low-self esteem
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Boys with XYY syndrome are more likely to have autism spectrum disorder and ADHD than those who do not have XYY syndrome.
What Causes XYY Syndrome?In most cases, XYY syndrome occurs due to a random chromosomal error before conception, when sperm cells form in the father's body. Usually, a single sperm cell carries either an X or Y chromosome.
If a cell division error occurs during spermatogenesis (production of sperm), a single sperm cell can contain two Y chromosomes rather than one. When this sperm cell fertilizes an egg and results in a pregnancy, a male is born with XYY syndrome, meaning every cell in his body has XYY chromosomes rather than XY chromosomes.
In rare cases, cell division errors can occur after conception and cause XYY syndrome. When this happens, a boy born with XYY syndrome may have an extra Y chromosome in some of his cells but not all. This is known as 46,XY or 47,XYY mosaicism.
The exact cause of cell division errors is not fully understood. XYY syndrome is genetic and not inherited, which means that XYY cannot be passed down through generations and does not tend to run in families.
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 TestingSome prenatal screening tests for genetic and chromosomal disorders can detect XYY syndrome during pregnancy. The most common test that detects chromosomal disorders is noninvasive prenatal testing (NIPT).
For a NIPT test, a blood sample taken from the vein of the gestational parent (parent giving birth) is sent to the lab, where small fragments of fetal DNA are isolated and analyzed to screen for chromosomal disorders. If the NIPT test result is positive for XYY syndrome, additional testing such as amniocentesis or chorionic villus sampling (CVS) tests can confirm the diagnosis.
Postnatal TestingAfter birth, a healthcare provider can diagnose XYY syndrome through a karyotype genetic test. A karyotype test analyzes the size, shape, and number of chromosomes in some of the body's cells. Karyotype testing may involve:
Blood test: Taking a small sample of blood from a vein
Buccal (cheek) swab: A swab is inserted into the mouth and rubbed across the inside of the cheek to gather cells
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.
XYY syndrome treatment options include:
Early intervention support: Children with XYY syndrome may benefit from early intervention services, such as speech and language therapy and occupational therapy, physical therapy, and behavioral therapy, to help them reach developmental milestones. These therapies can help improve gross and fine motor, communication, language, and social skills.
Educational support: Classroom support can help boys with XYY syndrome succeed in school. Boys who attend mainstream schools may need additional support, such as an individualized education plan (IEP) or a one-to-one or small instruction setting for certain subjects, particularly reading and writing.
Counseling: Families affected by XYY syndrome may benefit from counseling to better understand living with the syndrome and how best to support their family members. Those with emotional or behavioral issues, such as depression, anxiety, or social issues, may benefit from psychotherapy to help improve self-esteem, emotional well-being, and communication.
Medication: Healthcare providers may prescribe certain medications for conditions common in children with XYY syndrome, such as ADHD and acne.
Regular medical checkups: Regular visits with a healthcare provider are important for identifying any health problems or delays early so boys can receive the appropriate treatment as soon as possible.
Research suggests that the life span of people with XYY syndrome is approximately 12 years shorter than males without the condition. The increased risk of pulmonary (lung) and neurological conditions, such as asthma and seizure disorders, may affect the shorter life span.
Most boys and men with XYY syndrome live full lives. They go through puberty normally and can have children and careers, as well as a positive impact on their communities.
Coping With XYY SyndromeGetting a diagnosis of XYY syndrome, whether your own or your child's, can be difficult to process. Living with XYY syndrome can present unique challenges, and it's normal to have concerns about what the future may hold.
It can be helpful to learn as much as possible about XYY syndrome and the various therapies and early interventions that can positively impact the lives of those with the condition. Work closely with a healthcare provider to identify and treat any health, behavioral, or developmental concerns, and be in contact family members and friends for emotional support.
You may find value in reaching out to an organization that provides support, education, and resources to families affected by chromosome variations, such as AXYS, the Association for X and Y Chromosome Variations.
SummaryXYY syndrome occurs when a male is born with two Y chromosomes rather than one, as usual. Some people born with the condition have physical characteristics and behavioral symptoms, while others do not. Men and boys with XYY syndrome are often taller than average, and may have a curved pinky finger, low muscle tone, or flat feet.
Developmental delays, learning disabilities, and social and emotional challenges are common in boys born with an extra Y chromosome. XYY syndrome is associated with an increased risk of autism spectrum disorder and ADHD.
What Is Down Syndrome, A Condition New Edition Of Barbie Portrays?
© Provided by DNADown syndrome is a genetic disorder that occurs due to the presence of an extra copy of chromosome 21. Normally, humans have 23 pairs of chromosomes, but individuals with Down syndrome have three copies of chromosome 21, resulting in a total of 47 chromosomes. This extra genetic material affects the way the body and brain develop, leading to characteristic physical and cognitive differences.
Some common physical characteristics of individuals with Down syndrome include almond-shaped eyes that slant upward, a small nose and mouth, a short neck, small stature, and low muscle tone. They may also have heart defects, hearing and vision problems, and digestive issues.
Cognitively, individuals with Down syndrome may have intellectual disabilities that can range from mild to moderate, as well as delays in speech and language development. They may also experience behavioral and social challenges, such as difficulty with social interactions and communication.
While there is no cure for Down syndrome, early interventions and therapies can help individuals with the condition reach their full potential and lead fulfilling lives. With appropriate medical care and support, many individuals with Down syndrome can live into adulthood and beyond.
Some more common physical features of Down syndrome include:
Also read: What is impostor syndrome? Know how can one deal with this disorder
Barbie Releases New Doll With Down Syndrome In New Lineup Of Inclusive Figures
Mattel continues to strive for inclusion by releasing Barbie doll with Down syndrome
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Mattel worked with the National Down Syndrome Society to design a new Barbie doll with Down syndrome. Barbie's physical features, outfit and accessories are meant to reflect what living with the condition is like.
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The doll, which the company says is the first Barbie with Down syndrome, wears pink ankle foot orthoses to support her feet and ankles, and dons several other accessories that promote Down syndrome awareness or are commonly used by people with the disorder.
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The new doll is part of Barbie's 2023 Fashionista line, which the company describes as an "inclusive range" of dolls "designed to reflect the world kids see today."
Previous dolls in Barbie's Fashionista lineup have included a doll with hearing aids, dolls who come with a wheelchair and ramp and a Barbie and Ken who have a skin condition called vitiligo.
"Our goal is to enable all children to see themselves in Barbie, while also encouraging children to play with dolls who do not look like themselves," said Lisa McKnight, a Mattel executive vice president, in a press release.
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© Mattel A new Barbie doll represents different aspects of what living with Down syndrome is like. New Barbie's accessories, wardrobeBesides the pink braces she wears on her feet, Barbie represents these aspects Down syndrome:
Down syndrome is a condition in which a person is born with an extra chromosome, the X-shaped packages that hold our genes.
Babies with Down syndrome have an extra copy of one of these chromosomes, chromosome 21.
This extra copy changes how the baby's body and brain develop, which can cause both mental and physical challenges for the baby, according to the CDC.
Each year, about 6,000 babies born in the United States have Down syndrome. That means Down syndrome occurs in about 1 in every 700 babies, the CDC says.
Even though people with Down syndrome "might act and look similar," each person has different abilities, the CDC says on its website.
"This means so much for our community, who for the first time, can play with a Barbie doll that looks like them," said Kandi Pickard, National Down Syndrome Society President and CEO. "This Barbie serves as a reminder that we should never underestimate the power of representation. It is a huge step forward for inclusion and a moment that we are celebrating."
This article originally appeared on USA TODAY: Barbie releases new doll with Down syndrome in new lineup of inclusive figures
