48,XYYY syndrome
Findings
No curated finding names 48,XYYY syndrome yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
48,XYYY syndrome is a rare Y chromosome number anomaly that affects only males and is characterized by mild-moderate developmental delay (especially speech), normal to mild intellectual disability, large, irregular teeth with poor enamel, tall stature and acne. Radioulnar stenosis and clinodactyly have also been associated. Boys generally present normal genitalia, while hypogonadism and infertility is frequently reported in adult males.
Definition from the Mondo Disease Ontology (MONDO:0020469), read 2026-09-29. CC BY 4.0.
Features
31 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Abnormal dermatoglyphicsHPOHP:0007477
- Very frequent (80% to 99% of cases)
- Abnormal foot morphologyHPOHP:0001760
- Very frequent (80% to 99% of cases)
- Abnormal renal morphologyHPOHP:0012210
- Very frequent (80% to 99% of cases)
- AcneHPOHP:0001061
- Very frequent (80% to 99% of cases)
- Aggressive behaviorHPOHP:0000718
- Very frequent (80% to 99% of cases)
- AsthmaHPOHP:0002099
- Very frequent (80% to 99% of cases)
- Atypical behavior
Show the remaining 19
- EpicanthusHPOHP:0000286
- Very frequent (80% to 99% of cases)
- Feeding difficultiesHPOHP:0011968
- Very frequent (80% to 99% of cases)
- Global developmental delayHPOHP:0001263
- Very frequent (80% to 99% of cases)
- High palateHPOHP:0000218
- Very frequent (80% to 99% of cases)
- HypertelorismHPOHP:0000316
- Very frequent (80% to 99% of cases)
- ImpulsivityHPOHP:0100710
- Very frequent (80% to 99% of cases)