pentasomy X
MONDO:0015228Mondo
Findings
No curated finding names pentasomy X yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Pentasomy X is a sex chromosome anomaly caused by the presence of three extra X chromosomes in females (49,XXXXX instead of 46,XX).
Definition from the Mondo Disease Ontology (MONDO:0015228), read 2026-09-29. CC BY 4.0.
Features
22 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.
- HypotoniaHPOHP:0001252
- Very frequent (80% to 99% of cases)
- Posteriorly rotated earsHPOHP:0000358
- Very frequent (80% to 99% of cases)
- Camptodactyly of fingerHPOHP:0100490
- Frequent (30% to 79% of cases)
- Clinodactyly of the 5th fingerHPOHP:0004209
- Frequent (30% to 79% of cases)
- Global developmental delayHPOHP:0001263
- Frequent (30% to 79% of cases)
- HypertelorismHPOHP:0000316
- Frequent (30% to 79% of cases)
- Intellectual disabilityHPOHP:0001249
- Frequent (30% to 79% of cases)
- MicrocephalyHPOHP:0000252
- Frequent (30% to 79% of cases)
- MicrognathiaHPOHP:0000347
- Frequent (30% to 79% of cases)
- PlagiocephalyHPOHP:0001357
- Frequent (30% to 79% of cases)
- Radioulnar synostosisHPOHP:0002974
- Frequent (30% to 79% of cases)
- Short footHPOHP:0001773
- Frequent (30% to 79% of cases)
Show the remaining 10
- Short statureHPOHP:0004322
- Frequent (30% to 79% of cases)
- Small handHPOHP:0200055
- Frequent (30% to 79% of cases)
- StrabismusHPOHP:0000486
- Frequent (30% to 79% of cases)
- Upslanted palpebral fissureHPOHP:0000582
- Frequent (30% to 79% of cases)
- Wide nasal bridgeHPOHP:0000431
- Frequent (30% to 79% of cases)
- Abnormal cardiac septum morphologyHPOHP:0001671
- Occasional (5% to 29% of cases)
Where it sits
Other names
7 names
Resolves to: pentasomy X
- Also called
- 49, XXXXX syndrome49,XXXXX syndromePenta X Syndromepenta-XPentasomy type Xpoly-XXXXXX syndrome