Unusual Neonatal Presentation of 48,XXYY
Dual presentation expands known phenotypic spectrum of the syndrome
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By
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Jess Allerton
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February 10, 2026
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Clinical Scorecard: Unusual Neonatal Presentation of 48,XXYY
At a Glance
| Category | Detail |
|---|
| Condition | 48,XXYY syndrome |
| Key Mechanisms | Sex chromosome aneuploidy with ambiguous genitalia and congenital heart defects. |
| Target Population | Newborns, particularly males with disorders of sex development. |
| Care Setting | Neonatal intensive care unit (NICU). |
Key Highlights
- Estimated occurrence of 48,XXYY syndrome is 1 in 18,000 to 1 in 50,000 live male births.
- Ambiguous genitalia and Tetralogy of Fallot (TOF) are rare presentations.
- Early genetic testing is crucial for diagnosis in newborns with ambiguous genitalia.
- Congenital heart defects are present in over half of patients with 48,XXYY syndrome.
- This case expands the known clinical spectrum of 48,XXYY syndrome.
Guideline-Based Recommendations
Diagnosis
- Perform chromosomal analysis in cases of ambiguous genitalia.
Management
- Multidisciplinary management including pediatric endocrinology, cardiology, urology, and medical genetics.
Monitoring & Follow-up
- Monitor for developmental delays and endocrine concerns.
Risks
- Increased risk of congenital heart defects, particularly septal or valvular defects.
Patient & Prescribing Data
Preterm infants with ambiguous genitalia and congenital heart defects.
Early intervention and comprehensive evaluation are essential.
Clinical Best Practices
- Conduct pelvic ultrasonography to assess for testicular presence and renal abnormalities.
- Ensure timely genetic testing for accurate diagnosis.
References
