tetrasomy X
MONDO:0019525Mondo
Findings
No curated finding names tetrasomy X yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Tetrasomy X is a sex chromosome anomaly caused by the presence of two extra X chromosomes in females (48,XXXX instead of 46,XX).
Definition from the Mondo Disease Ontology (MONDO:0019525), read 2026-09-29. CC BY 4.0.
Features
16 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.
- Abnormality of the dentitionHPOHP:0000164
- Frequent (30% to 79% of cases)
- Cognitive impairmentHPOHP:0100543
- Frequent (30% to 79% of cases)
- EpicanthusHPOHP:0000286
- Frequent (30% to 79% of cases)
- Global developmental delayHPOHP:0001263
- Frequent (30% to 79% of cases)
- HypertelorismHPOHP:0000316
- Frequent (30% to 79% of cases)
- HypotoniaHPOHP:0001252
- Frequent (30% to 79% of cases)
- Joint hypermobilityHPOHP:0001382
- Frequent (30% to 79% of cases)
- Radioulnar synostosisHPOHP:0002974
- Frequent (30% to 79% of cases)
- Specific learning disabilityHPOHP:0001328
- Frequent (30% to 79% of cases)
- StrabismusHPOHP:0000486
- Frequent (30% to 79% of cases)
- Upslanted palpebral fissureHPOHP:0000582
- Frequent (30% to 79% of cases)
- Abnormal cardiovascular system morphologyHPOHP:0030680
- Occasional (5% to 29% of cases)
Show the remaining 4
- Abnormality of immune system physiologyHPOHP:0010978
- Occasional (5% to 29% of cases)
- BrachydactylyHPOHP:0001156
- Occasional (5% to 29% of cases)
- Clinodactyly of the 5th fingerHPOHP:0004209
- Occasional (5% to 29% of cases)
- Hip dysplasiaHPOHP:0001385
- Occasional (5% to 29% of cases)
Where it sits
Other names
4 names
Resolves to: tetrasomy X
- Also called
- 48,XXXX syndromequadruple Xtetra Xtetrasomy type X