tetrasomy 18p
MONDO:0013668Mondo
Findings
No curated finding names tetrasomy 18p yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Tetrasomy 18p is a very rare structural chromosomal anomaly affecting multiple body systems and characterized clinically by craniofacial abnormalities, delayed development, cognitive impairment, changes in muscle tone, distinctive facial features, and rarely renal malformations.
Definition from the Mondo Disease Ontology (MONDO:0013668), read 2026-09-29. CC BY 4.0.
Features
18 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 neuronal migrationHPOHP:0002269
- Very frequent (80% to 99% of cases)
- Abnormality of the faceHPOHP:0000271
- Very frequent (80% to 99% of cases)
- Long philtrumHPOHP:0000343
- Very frequent (80% to 99% of cases)
- MicrocephalyHPOHP:0000252
- Very frequent (80% to 99% of cases)
- EpicanthusHPOHP:0000286
- Frequent (30% to 79% of cases)
- Posteriorly rotated earsHPOHP:0000358
- Frequent (30% to 79% of cases)
- AchalasiaHPOHP:0002571
- Occasional (5% to 29% of cases)
- Downslanted palpebral fissuresHPOHP:0000494
- Occasional (5% to 29% of cases)
- Facial asymmetryHPOHP:0000324
- Occasional (5% to 29% of cases)
- Gait disturbanceHPOHP:0001288
- Occasional (5% to 29% of cases)
- Intellectual disabilityHPOHP:0001249
- Occasional (5% to 29% of cases)
- Large handsHPOHP:0001176
- Occasional (5% to 29% of cases)
Show the remaining 6
- Narrow mouthHPOHP:0000160
- Occasional (5% to 29% of cases)
- ScoliosisHPOHP:0002650
- Occasional (5% to 29% of cases)
- SeizureHPOHP:0001250
- Occasional (5% to 29% of cases)
- Short noseHPOHP:0003196
- Occasional (5% to 29% of cases)
- SyncopeHPOHP:0001279
- Occasional (5% to 29% of cases)
- Thin vermilion borderHPOHP:0000233
- Occasional (5% to 29% of cases)
Where it sits
Other names
2 names
Resolves to: tetrasomy 18p
- Also called
- Isochromosome 18ptetrasomy type 18P