49 Xxxxy Syndrome C0265499
A rare chromosomal disorder in males with multiple extra X chromosomes, causing severe intellectual disability, skeletal abnormalities, and hypogonadism.
Key facts at a glance
- ICD-10
- Q89.9
- ICD-11
- LA00.0
- Body system
- congenital
- Severity
- severe
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Warning signs - seek immediate care
Seizures
Recurrent seizure activity due to abnormal electrical activity in the brain.
Seek immediate emergency care for any seizure episode lasting more than 5 minutes or if recurrent seizures occur.
Congenital heart defects
Structural heart abnormalities present at birth, which may require surgical intervention.
Seek immediate medical attention if symptoms of heart failure develop such as difficulty breathing or bluish skin discoloration.
Severe intellectual disability
(neurologic)Significant cognitive impairment ranging from moderate to profound intellectual disability affecting learning and reasoning abilities.
Frequency: 100% of patients
Global developmental delay
(constitutional)Significant delays in reaching developmental milestones including motor skills, speech, and language development.
Frequency: 100% of patients
Hypotonia
(musculoskeletal)Reduced muscle tone resulting in floppy or loose muscles, affecting movement and posture.
Frequency: 90-95% of patients
Genital abnormalities
(genitourinary)Underdeveloped male genitalia including small penis, undescended testes, or other structural abnormalities.
Frequency: 80-90% of patients
Skeletal abnormalities
(musculoskeletal)Various bone and joint abnormalities including curved spine, abnormal bone development, or joint contractures.
Frequency: 70-80% of patients
Short stature
(constitutional)Abnormally low height compared to peers due to underlying chromosomal abnormality affecting growth.
Frequency: 70-80% of patients
Distinctive facial features
(dermatologic)Characteristic facial appearance including widely spaced eyes, flat nasal bridge, or other dysmorphic features.
Frequency: 60-70% of patients
Behavioral problems
(neurologic)Autistic-like behaviors, hyperactivity, aggression, or other neurobehavioral issues may be present.
Frequency: 60-70% of patients
Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Targeted drug therapy with dose adjustment
Active treatment with regular monitoring by a healthcare provider is recommended.
Testosterone replacement therapy
Hormone therapy to address androgen deficiency common in XXXYY syndrome, promoting secondary sexual characteristics and improving energy levels.
Developmental and behavioral intervention
Specialized behavioral therapy and educational support addressing developmental delays, learning disabilities, and social skill deficits associated with the chromosomal abnormality.
Additional treatment options
Motor skill development program
Physical therapy focused on improving coordination, muscle tone, and gross motor skills commonly affected in XXXYY syndrome patients.
physical_therapyComprehensive multidisciplinary surveillance
Regular monitoring for associated conditions including cardiac anomalies, thyroid dysfunction, and renal abnormalities through scheduled assessments.
monitoringSpeech and language therapy
Specialized speech therapy addressing expressive and receptive language delays, articulation issues, and communication challenges.
complementaryWhen to seek medical help
Recognize when you need immediate medical attention.
See a doctor within 24 hours
Moderate to severe symptoms that may indicate worsening of this condition. Prompt medical evaluation is recommended.
Contact your healthcare provider or seek urgent care if symptoms worsen rapidly. Go to the emergency department for life-threatening symptoms.
Frequently asked questions
Common questions about this topic.
What is 49 Xxxxy Syndrome C0265499?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Tartaglia N, Davis S, Hench A, et al. A New Look at XXYY Syndrome: Medical and Psychological Features. Am J Med Genet A. 2008.
Jones KL, Jones MC, del Campo Casanelles. Smith's Recognizable Patterns of Human Malformation. 7th ed. Elsevier; 2013.
Linden MG, Bender BG, Robinson A. Sex Chromosome Tetrasomy and Pentasomy. Pediatrics. 1995.
Visootsak J, Graham JM Jr. Social Functioning in Sex Chromosome Disorders. In: Updates in Human Chromosome Disorders. IntechOpen; 2019.
McCandless SE, Committee on Genetics. Clinical Report—Health Supervision for Children With Sex Chromosome Abnormalities. American Academy of Pediatrics; 2015.
Samango-Sprouse C, Lasutschinkow G, Gass K, et al. The Incidence and Frequency of X-Chromosome Variations in Infancy. Am J Med Genet C Semin Med Genet. 2020.
Graham JM Jr, Bashir AS, Stark RE, et al. Oral and Written Language Abilities of XXYY Syndrome: Comparison with XXY and XYY. J Pediatr. 2015.
Kelley M, Kigar S, Martin A. Neurodevelopmental and Psychological Profile in X-Chromosome Polysomies. J Dev Behav Pediatr. 2019.
Abramsky L, Chapple J. Sex Chromosome Aneuploidies: Counseling and Management. Royal College of Obstetricians and Gynaecologists Guidelines. RCOG; 2018.
National Institutes of Health. Genetics Home Reference: 49,XXXXY Syndrome. NIH/NLM; 2020.
Medication Comparisons
Compare medications used to treat 49 Xxxxy Syndrome C0265499. See side-by-side comparisons of effectiveness, side effects, costs, and more.
View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy