49 Xxxyy Syndrome C4749586
A rare chromosomal condition in males with extra X and Y chromosomes, causing developmental delays, learning difficulties, and distinct physical features. Management focuses on supportive care and early intervention services.
Key facts at a glance
- ICD-10
- Q89.9
- ICD-11
- LA00.0
- Body system
- congenital
- Severity
- moderate
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Warning signs - seek immediate care
Congenital heart defects
Structural heart abnormalities such as septal defects or valve abnormalities present at birth.
URGENT: Any signs of heart failure or cyanosis require immediate medical evaluation.
Global developmental delay
(neurologic)Delayed achievement of developmental milestones such as sitting, walking, and talking compared to typical age expectations.
Frequency: 80-90% of patients
Intellectual disability
(neurologic)Mild to moderate intellectual impairment affecting cognitive function, reasoning, and problem-solving abilities.
Frequency: 80-90% of patients
Speech and language delays
(neurologic)Delayed speech development and difficulties with language expression and comprehension.
Frequency: 70-80% of patients
Hypotonia
(neurologic)Reduced muscle tone resulting in floppiness and decreased muscle strength during infancy and early childhood.
Frequency: 70-80% of patients
Small testes and infertility
(genitourinary)Underdeveloped testes and impaired sperm production leading to infertility in adulthood.
Frequency: 60-70% of patients
Delayed puberty
(endocrine)Onset of puberty occurs later than average, often requiring hormonal intervention.
Frequency: 50-60% of patients
Tall stature
(constitutional)Excessive linear growth, particularly in long limbs, becoming more apparent during childhood and adolescence.
Frequency: 50-60% of patients
Learning difficulties
(neurologic)Challenges with academic learning, reading, writing, and mathematical concepts despite typical intelligence.
Frequency: 60-70% of patients
Behavioral challenges
(neurologic)Attention difficulties, impulsivity, anxiety, or autistic-like social and communication differences.
Frequency: 40-50% 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
Comprehensive Developmental Surveillance
Longitudinal monitoring of growth, endocrine function, cognitive development, and behavioral milestones through multidisciplinary assessments. Regular screening allows early identification of emerging concerns.
Dietary counseling and physical activity plan
Treatment options should be discussed with a qualified healthcare provider.
Behavioral and Educational Interventions
Individualized educational support, behavioral therapy, and social skills training addressing learning disabilities, attention deficits, and behavioral challenges commonly associated with the syndrome.
Additional treatment options
Endocrine Hormone Replacement
Testosterone replacement therapy for hypogonadism and other hormone therapies as indicated by laboratory assessments. Individualized dosing based on developmental stage and endocrine panel results.
medicationMotor Skills Development Program
Early intervention physical therapy focusing on gross and fine motor development, coordination, and muscle tone optimization. Therapists address hypotonia and promote age-appropriate motor milestones.
physical_therapyStructured Supportive Environment
Creation of a structured daily routine with appropriate sensory accommodations, clear communication strategies, and consistent behavioral expectations to maximize functional abilities.
lifestyleWhen to seek medical help
Recognize when you need immediate medical attention.
Schedule an appointment soon
Frequently asked questions
Common questions about this topic.
What is 49 Xxxyy Syndrome C4749586?
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.
Borghgraef K, Fryns JP, Van den Berghe H. The XXYY syndrome: a review. Genetic Counseling. 1991.
Tartaglia N, Davis S, Hansen R, et al. 49,XXYY Syndrome: A Report of Two Adult Cases and Review of Clinical Features. American Journal of Medical Genetics Part A. 2008.
Visootsak J, Graham JM Jr. Social function in multiple X and Y chromosome disorders: XXYY, XYY, XXY, and XXX. International Journal of Disability Development and Education. 2009.
Radicioni AF, Ferlin A, Balercia G, et al. Consensus statement on diagnosis and clinical management of Klinefelter syndrome. Journal of Endocrinological Investigation. 2010.
Groth KA, Skakkebæk A, Høst C, Gravholt CH, Bojesen A. Clinical review: Klinefelter syndrome—a clinical update. Journal of Clinical Endocrinology and Metabolism. 2013.
Samango-Sprouse C, Brooks R,Counts S, et al. The neurodevelopment of infants with 49,XXYY and 49,XXXXY. Journal of Pediatric Genetics. 2017.
Skakkebæk A, Gravholt CH, Rasmussen PM, et al. Klinefelter syndrome: integrating genetics, neuropsychology, and endocrinology. Endocrine Reviews. 2022.
Jones KL, Jones MC, del Campo Casanelles. Smith's Recognizable Patterns of Human Malformation. 8th ed. Elsevier; 2022.
Marzi M, Aliberti M, D'Alberto M, et al. 49,XXYY syndrome: clinical phenotype, psychological aspects and therapeutic approaches. Italian Journal of Pediatrics. 2023.
Genetics Home Reference. 49,XXYY syndrome. U.S. National Library of Medicine. Updated 2020.
Medication Comparisons
Compare medications used to treat 49 Xxxyy Syndrome C4749586. 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 27, 2026. · Read our editorial policy