47, XYY syndrome
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
Age of Onset
Autosomal dominant ?A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease
Autosomal recessive ?Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype
X-linked dominant ?X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
X-linked recessive ?Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder
Mitochondrial or multigenic ?Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.
Multigenic or multifactor ?Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.
Other Names (AKA)
YY syndrome; XYY syndrome; XYY Karyotype;
Chromosome Disorders; Congenital and Genetic Diseases
47, XYY syndrome is caused by having an extra copy of the
Other signs and symptoms of 47, XYY syndrome may include asthma, dental problems, and acne. Boys with the syndrome don’t typically have physical features different from most people, but they may be taller than expected. These boys are not expected to have differences in the appearance of the sex
Most boys with 47, XYY syndrome go through normal sexual development, and fertility is expected to be normal. However, some boys with the syndrome may develop testicular failure (when the
This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.
|Medical Terms||Other Names||
|80%-99% of people have these symptoms|
|Delayed speech and language development||
Deficiency of speech development
Delayed language development
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
[ more ]
Low set ears
[ more ]
Increased body height
|30%-79% of people have these symptoms|
|Attention deficit hyperactivity disorder||
Attention deficit disorder
Attention deficit-hyperactivity disorder
Childhood attention deficit/hyperactivity disorder
[ more ]
Night blindness since birth
Widely spaced eyes
[ more ]
|Impaired social interactions||
Impaired social interaction
Poor social interactions
[ more ]
Mental retardation, nonspecific
[ more ]
Increased size of skull
Large head circumference
[ more ]
Low muscle tone, in neonatal onset
|Specific learning disability||0001328|
|5%-29% of people have these symptoms|
|Abnormality of brainstem morphology||
Abnormal shape of brainstem
Absent sperm in semen
[ more ]
|Dysgenesis of the cerebellar vermis||0002195|
Too much cerebrospinal fluid in the brain
|Increased circulating gonadotropin level||
Elevated serum gonadotropins
[ more ]
|Increased serum testosterone level||0030088|
[ more ]
Low sperm count
Boys with 47, XYY syndrome have one X chromosome and two Y chromosomes in each cell of the body. This typically happens due to a random event when a sperm cell is formed that causes the sperm cell to have two Y chromosomes. When a sperm that has two Y chromosomes fertilizes an egg (which has an X chromosome), the resulting baby will be a male with two Y chromosomes and one X chromosome. It is also possible that a similar random event could occur very early in an embryo’s development. This can produce a boy who has some cells that have two sex chromosomes and some cells that have an extra Y chromosome.
It is not fully understood why an extra copy of the Y chromosome causes the features associated with 47, XYY syndrome. It is thought that the tall stature seen in some males with the syndrome is caused by having an extra copy of a
Karyotype: a test that is used to view all the chromosomesin a cell
- Chromosomal microarray: a test that looks for extra or missing chromosomes or pieces of chromosomes
In some cases, 47, XYY syndrome may be suspected prenatally based on routine
It is thought that some people who have 47, XYY syndrome are never diagnosed because they do not have severe signs or symptoms of the syndrome.
Other management options for boys with 47, XYY syndrome may include behavioral therapy or medications for boys with attention deficit hyperactivity disorder (ADHD) or behavioral problems. If autism spectrum disorder is present, applied behavioral analysis (ABA) therapy may be recommended. In some cases, hormonal therapy may be used.
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.
Association for X and Y Chromosome Variations (AXYS)
P.O. Box 861
Mendenhall, PA 19357
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.
- 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.
- 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.
- 47,XYY syndrome. Genetics Home Reference. January 2009; https://ghr.nlm.nih.gov/condition/47xyy-syndrome.
- Ross J and Bishop D. XYY. Unique. 2014; https://www.rarechromo.org/information/Chromosome_Y/XYY%20FTNW.pdf.
- Lenroot RK. XYY Syndrome. National Organization for Rare Disorders. 2012; https://rarediseases.org/rare-diseases/xyy-syndrome/.
- Schedit L, Sanabe ME, and Diniz MB. Oral, physical, and behavioral aspects of patient with chromosome 47, XYY syndrome. Journal of the Indian Society of Pedodontics and Preventive Dentistry. October-December 2015; 33(4):347-350. https://www.ncbi.nlm.nih.gov/pubmed/26381641.
- Frequently Asked Questions: X and Y Chromosome Variations. The Association for X and Y Chromosome Variations (AXYS). https://genetic.org/variations/faq/.
- Borjian Boroujeni P, Sabbaghian M, Vosough Dizaji A, Zarei Moradi S, Almadani N, Mohammadpour Lashkari F, Zamanian MR, and Mohseni Meybodi A. Clinical aspects of infertile 47,XYY patients: a retrospective study. Human Fertility. July 18, 2017; https://www.ncbi.nlm.nih.gov/pubmed/28715980.
- Samango-Sprouse C, Stapleton EJ, Lawson P, Mitchell F, Sadeghin T, Powell S, and Gropman AL. Positive effects of early androgen therapy on the behavioral phenotype of boys with 47,XXY. Am J Med Genet C Semin Med Genet. June 2015; 169(2):150-157. https://www.ncbi.nlm.nih.gov/pubmed/25939399.