47, XYY syndrome

Información en español Title

Other Names:

YY syndrome; XYY syndrome; XYY Karyotype; YY syndrome; XYY syndrome; XYY Karyotype; Jacobs syndrome See More

Categories:

Chromosome Disorders; Congenital and Genetic Diseases

Summary Summary

47, XYY syndrome is a condition in males characterized by features that occur due to having an extra copy of the Y chromosome in each cell. Signs and symptoms can vary and range from barely noticeable to more severe; many men with the extra Y chromosome are completely unaware of its presence.^[1] Appearance and intelligence are usually normal, but learning disabilities may be present. Other signs and symptoms may include autism spectrum disorder (usually on the milder end); speech or motor delay; low muscle tone; asthma; tall stature; impaired social skills; ADHD; and/or anxiety or mood disorders.^[1]^[2] While sexual development and fertility is usually normal, some adolescents and adults have testicular failure (where the testis can't produce sperm or testosterone).^[1] 47, XYY syndrome usually is not inherited, occurring due to a random event in the formation of a sperm cell prior to conception.^[3] Management depends on the symptoms in each person, and may include intervention or therapies for developmental delays and for behavior or mood disorders, and/or special education.^[1]

Some males with 47,XYY syndrome have an extra Y chromosome in only some of their cells. This phenomenon is called 46,XY/47,XYY mosaicism.^[4]

Last updated: 10/16/2017

Symptoms Symptoms

The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.

Signs and Symptoms	Approximate number of patients (when available)
Delayed speech and language development	Very frequent (present in 80%-99% of cases)
Low-set ears	Very frequent (present in 80%-99% of cases)
Malar flattening	Very frequent (present in 80%-99% of cases)
Motor delay	Very frequent (present in 80%-99% of cases)
Tall stature	Very frequent (present in 80%-99% of cases)
Asthma	Frequent (present in 30%-79% of cases)
Attention deficit hyperactivity disorder	Frequent (present in 30%-79% of cases)
Congenital stationary night blindness	Frequent (present in 30%-79% of cases)
Finger clinodactyly	Frequent (present in 30%-79% of cases)
Hypertelorism	Frequent (present in 30%-79% of cases)
Impaired social interactions	Frequent (present in 30%-79% of cases)
Impulsivity	Frequent (present in 30%-79% of cases)
Intellectual disability	Frequent (present in 30%-79% of cases)
Macrocephaly	Frequent (present in 30%-79% of cases)
Neonatal hypotonia	Frequent (present in 30%-79% of cases)
Specific learning disability	Frequent (present in 30%-79% of cases)
Abnormality of brainstem morphology	Occasional (present in 5%-29% of cases)
Azoospermia	Occasional (present in 5%-29% of cases)
Cerebellar dysplasia	Occasional (present in 5%-29% of cases)
Cryptorchidism	Occasional (present in 5%-29% of cases)
Dysgenesis of the cerebellar vermis	Occasional (present in 5%-29% of cases)
Hydrocephalus	Occasional (present in 5%-29% of cases)
Hypospadias	Occasional (present in 5%-29% of cases)
Increased circulating gonadotropin level	Occasional (present in 5%-29% of cases)
Increased serum testosterone level	Occasional (present in 5%-29% of cases)
Macroorchidism	Occasional (present in 5%-29% of cases)
Male infertility	Occasional (present in 5%-29% of cases)
Micropenis	Occasional (present in 5%-29% of cases)
Oligospermia	Occasional (present in 5%-29% of cases)
Seizures	Occasional (present in 5%-29% of cases)
Varicocele	Occasional (present in 5%-29% of cases)

Last updated: 10/1/2017

Cause Cause

47,XYY syndrome is caused by the presence of an extra copy of the Y chromosome in each of a male's cells.^[3] This is typically due to a random event during the formation of a sperm cell in the father, usually before conception (fertilization of the egg). In this case, the father's two Y chromosomes do not separate when sperm cells are being made. If two Y chromosomes are present in a sperm that fertilizes an egg (with an X chromosome), the resulting embryo will be a male with an extra Y chromosome. It is also possible that a similar random event could occur very early in an embryo's development. This can produce 46,XY/47,XYY mosaics. ^[2] It is not fully understood why an extra copy of the Y chromosome leads to an increased risk for the features associated with 47, XYY syndrome in some males.^[3]

Importantly, there is nothing either parent can do (or not do) to cause or prevent 47, XYY syndrome.

Last updated: 10/16/2017

Inheritance Inheritance

47, XYY syndrome is usually not inherited. It is typically due to a random event during the formation of a sperm cell.^[3]

Recurrence of 47, XYY syndrome in a family is rare. The recurrence risk for siblings and other family members is not thought to be increased. Additionally, men with 47, XYY are not reported to have an increased risk for a child with a chromosome variation.^[5]^[6]

People with personal questions about recurrence risks are encouraged to speak with a genetic counselor or other genetic professional.

Last updated: 10/16/2017

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Organizations Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Association for X and Y Chromosome Variations (AXYS)
P.O. Box 861
Mendenhall, PA 19357
Toll-free: 888-999-9428
E-mail: info@genetic.org
Website: http://www.genetic.org
Chromosome Disorder Outreach
PO Box 724
Boca Raton, FL 33429
Telephone: 561-395-4252
E-mail: info@chromodisorder.org
Website: http://www.chromodisorder.org
Unique – Rare Chromosome Disorder Support Group
G1, The Stables
Station Road West
Surrey
RH8 9EE
United Kingdom
Telephone: +44 (0)1883 723356
E-mail: info@rarechromo.org
Website: http://www.rarechromo.org

Do you know of an organization? Send us your suggestions.

Learn More Learn More

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

The Association for X and Y Chromosome Variations (AXYS) provides answers to frequently asked questions about 47, XYY syndrome. Click on the link above to view this information.
Genetics Home Reference (GHR) contains information on 47, XYY syndrome. This website is maintained by the National Library of Medicine.
The Merck Manuals Online Medical Library provides information on this condition for patients and caregivers.
The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
The Pacific Northwest Regional Genetics Group has developed a fact sheet on 47, XYY syndrome, including prenatal diagnosis. Click on the link above to view this information page.

In-Depth Information

The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
PubMed is a searchable database of medical literature and lists journal articles that discuss 47, XYY syndrome. Click on the link to view a sample search on this topic.

News & Events News & Events

News

Don’t Miss the NCATS Toolkit for Patient-Focused Therapy Development Event
August 31, 2017
Funding Opportunities Now Available for the Undiagnosed Diseases Network (UDN) Phase II
August 30, 2017
IRDiRC Goals 2017-2027: New Rare Disease Research Goals for the Next Decade
August 10, 2017
Developing a New Tool to Detect a Frequently Missed Sex Chromosome Disorder in Boys
August 25, 2015

Related Diseases Related Diseases

The following diseases are related to 47, XYY syndrome. If you have a question about any of these diseases, you can contact GARD.

Numeric sex chromosome variations

GARD Answers GARD Answers

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question

47,XYY syndrome was present in my first delivery. Is it likely to be repeated? What is the main cause of this syndrome? See answer
I have a 4 year old son who was diagnosed with XYY karotype about a year ago. Lately, he has had a lot of behavior issues; he is very strong and he does throw several temper tantrums a day. I am looking for any advice how I can redirect him and get through to him on a positive note. See answer

Have a question? Contact a GARD Information Specialist.

References References

Frequently Asked Questions Related to 47, XYY. The Association for X and Y Chromosome Variations (AXYS). 2016; https://genetic.org/variations/faq/.
XYY. Unique. 2014; http://www.rarechromo.org/information/Chromosome_Y/XYY%20FTNW.pdf.
47,XYY syndrome. Genetics Home Reference. January 2009; http://ghr.nlm.nih.gov/condition/47xyy-syndrome.
Y chromosome. Genetics Home Reference. 2010; http://ghr.nlm.nih.gov/chromosome/Y.
Harold Chen. XYY Syndrome. Atlas of Genetic Diagnosis and Counseling, Second Edition. US: Springer; 2012; 2221-2224.
Guy Bradley-Smith, Sally Hope, Helen V. Firth, Jane A. Hurst. Chromosomes. Oxford Handbook of Genetics. United States: Oxford University Press; 2010; 316.