National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

49, XXXYY syndrome



Other Names:
XXXYY syndrome
Categories:
This disease is grouped under:

49, XXXYY syndrome is a chromosome abnormality that occurs when a male inherits two extra copies of the X chromosome and one extra copy of the Y chromosome. The condition is extremely rare with only a handful of cases reported in the medical literature. Signs and symptoms associated with these cases include severe intellectual disability, distinctive facial features, normal to tall stature, gynecomastia, hypogonadism, and behavioral abnormalities. 49, XXXYY syndrome is likely caused by a mistake (called nondisjunction) that occurs at conception or during the formation of the sperm and/or egg. Treatment is based on the signs and symptoms present in each person.[1][2]
Last updated: 5/17/2016

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.

Showing of 30 |
Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Abnormal facial shape
Unusual facial appearance
0001999
Abnormal plantar dermatoglyphics
Abnormal prints on feet
0010506
Abnormality of the cerebral white matter 0002500
Ambiguous genitalia
Ambiguous external genitalia
Ambiguous external genitalia at birth
Intersex genitalia
[ more ]
0000062
Autistic behavior 0000729
Bilateral talipes equinovarus
Club foot on both sides
0001776
Decreased serum testosterone level
Decreased serum testosterone levels
Low serum testosterone level
Low serum testosterone levels
[ more ]
0040171
Decreased testicular size
Small testes
Small testis
[ more ]
0008734
Delayed skeletal maturation
Delayed bone maturation
Delayed skeletal development
[ more ]
0002750
Delayed speech and language development
Deficiency of speech development
Delayed language development
Delayed speech
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language delay
Language delayed
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay
[ more ]
0000750
Epicanthus
Eye folds
Prominent eye folds
[ more ]
0000286
Eunuchoid habitus 0003782
Finger clinodactyly 0040019
Gynecomastia
Enlarged male breast
0000771
Hypertelorism
Wide-set eyes
Widely spaced eyes
[ more ]
0000316
Increased circulating gonadotropin level
Elevated gonadotropins
Elevated serum gonadotropins
Gonadotropin excess
[ more ]
0000837
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ]
0001249
Low frustration tolerance 0000744
Low-set, posteriorly rotated ears 0000368
Male hypogonadism
Decreased function of male gonad
0000026
Mandibular prognathia
Big lower jaw
Increased projection of lower jaw
Increased size of lower jaw
Large lower jaw
Prominent chin
Prominent lower jaw
[ more ]
0000303
Micrognathia
Little lower jaw
Small jaw
Small lower jaw
[ more ]
0000347
Micropenis
Short penis
Small penis
[ more ]
0000054
Moderate global developmental delay 0011343
Narrow chest
Low chest circumference
Narrow shoulders
[ more ]
0000774
Primary gonadal insufficiency 0008193
Prominent forehead
Pronounced forehead
Protruding forehead
[ more ]
0011220
Recurrent upper respiratory tract infections
Recurrent colds
0002788
Ventriculomegaly 0002119
Wide nasal bridge
Broad nasal bridge
Broad nasal root
Broadened nasal bridge
Increased breadth of bridge of nose
Increased breadth of nasal bridge
Increased width of bridge of nose
Increased width of nasal bridge
Nasal bridge broad
Wide bridge of nose
Widened nasal bridge
[ more ]
0000431
Showing of 30 |
Last updated: 7/1/2020

Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • Orphanet lists international laboratories offering diagnostic testing for this condition.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • Orphanet lists European clinical trials, research studies, and patient registries enrolling people with this condition. 

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


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

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 49, XXXYY syndrome. Click on the link to view a sample search on this topic.

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.


  1. Linden MG, Bender BG, Robinson A. Sex chromosome tetrasomy and pentasomy. Pediatrics. 1995 Oct; 96(4 pt 1):672-682. https://www.ncbi.nlm.nih.gov/pubmed/7567329.
  2. Cowie VA, Singh KR, Wheater R. 49, XXXYY chromosome anomaly in a mentally retarded man. Br J Psychiatry. 1986 Feb; 148:210-212. https://www.ncbi.nlm.nih.gov/pubmed/3697588.