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The 48,XXYY syndrome represents a chromosomal anomaly of the aneuploidic type characterized by the presence of an extra X and Y chromosome in males.
Features include very common findings: Azoospermia, Infertility, Hypergonadotropic hypogonadism, and Intellectual disability and others; and common findings: Tall stature, Thick lower lip vermilion, Epicanthus, and Hypertelorism and others. 61 total HPO annotations.
Organ System | Phenotype Count | Example Features |
|---|---|---|
Brain and nerves | 11 | Intellectual disability, Global developmental delay, Abnormal speech pattern |
Biomarker and diagnostic research for 48,XXYY syndrome has been reported in the published literature.
Phenotype severity distribution: 7 very common features, 31 common features.
Estimated prevalence: Unknown (Unknown prevalence).
2 clinical trials registered, 2 recruiting. Interventions under study include other interventions. Research is primarily sponsored by academic and government institutions.
15 publications have been identified in PubMed for 48,XXYY syndrome. Research spans Case Report / Case Series (60%), Review / Meta-Analysis (20%), and Other (7%).
Research Type | Count | % of Total |
|---|---|---|
Patient case studies | 9 | 60% |
Data assembled from 5 of 12 sources · Last updated Sep 19, 2026, 4:31 PM UTC
European rare disease database
Genetic and Rare Diseases Info Center
Common questions about 48,XXYY syndrome
Head and neck |
4 |
Thick lower lip vermilion, Cleft palate, Long face |
Hormones | 3 | Infertility, Hypergonadotropic hypogonadism, Type II diabetes mellitus |
Digestive system | 3 | Constipation, Feeding difficulties in infancy, Gastroesophageal reflux |
Lungs and breathing | 3 | Asthma, Recurrent respiratory infections, Apnea |
Eyes | 2 | Strabismus, Nystagmus |
Blood and immune system | 2 | Recurrent respiratory infections, Lymphoma |
Bones and joints | 2 | Joint hypermobility, Sideways curvature of the spine (scoliosis) |
Growth and development | 1 | Tall stature |
Ears | 1 | Chronic otitis media |
Muscles | 1 | Low muscle tone (hypotonia) |
Arms and legs | 1 | Clinodactyly of the 5th finger |
Research summaries |
3 |
20% |
Other research | 1 | 7% |
Testing and diagnosis research | 1 | 7% |
Disease patterns and progression | 1 | 7% |
Carl A (2026). [PMID: 40799057](https://pubmed.ncbi.nlm.nih.gov/40799057/). *Am J Med Genet A*. [Diagnostic / Biomarker]
Gazzaz N (2026). [PMID: 41541050](https://pubmed.ncbi.nlm.nih.gov/41541050/). *Clin Case Rep*. [Case Report / Case Series]
Nocon K (2026). [PMID: 42282190](https://pubmed.ncbi.nlm.nih.gov/42282190/). *medRxiv*. [Epidemiology / Natural History]
Yücel İ (2026). [PMID: 41920252](https://pubmed.ncbi.nlm.nih.gov/41920252/). *Endocrine*. [Review / Meta-Analysis]
Francisco T (2025). [PMID: 40984948](https://pubmed.ncbi.nlm.nih.gov/40984948/). *Cureus*. [Case Report / Case Series]
Olaya M (2025). [PMID: 41488144](https://pubmed.ncbi.nlm.nih.gov/41488144/). *Front Endocrinol (Lausanne)*. [Case Report / Case Series]
Dreyer J (2025). [PMID: 40190105](https://pubmed.ncbi.nlm.nih.gov/40190105/). *Am J Med Genet A*. [Other]
Vavasseur T (2025). [PMID: 40339461](https://pubmed.ncbi.nlm.nih.gov/40339461/). *J Fr Ophtalmol*. [Case Report / Case Series]
Batista RL (2025). [PMID: 41379151](https://pubmed.ncbi.nlm.nih.gov/41379151/). *Einstein (Sao Paulo)*. [Case Report / Case Series]
Ambulkar PS (2025). [PMID: 40740624](https://pubmed.ncbi.nlm.nih.gov/40740624/). *J Hum Reprod Sci*. [Case Report / Case Series]
AI-curated news mentioning 48,XXYY syndrome
Updated Jul 8, 2026
A new treatment for children aged 2 or older with sickle cell disease has been approved by the U.S. Food & Drug Administration. In a press release on Wednesday, the FDA announced it had approved Casgevy, the first gene therapy for children with sickle cell disease. (NewsNation) — A new treatment for children aged 2 or older with sickle cell disease has been approved by the Food & Drug Administration (FDA). In a Wednesday news release, the FDA announced it had approved Casgevy, the first gene therapy for children with the disease. “Casgevy is a gene therapy consisting of the patient’s own (autologous) hematopoietic (blood) stem cells, administered as a one-time single dose for intravenous infusion,” the release noted. “Pediatric patients as young as 2 years of age can now access a critical additional treatment option to treat these debilitating, life-threatening diseases,” Karim Mikhail, the acting director of the Center for Biologics Evaluation and Research, wrote. “These disorders carry a heavy burden for children and their families, affecting growth, development, and long-term health in profound ways,” Megha Kaushal, acting deputy director of the Office of Therapeutic Products in CBER, said in the release.