trisomy 18p
MONDO:0015740Mondo
Findings
No curated finding names trisomy 18p yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
Trisomy 18p is an extremely rare chromosomal anomaly with a poorly defined clinical phenotype. Reported manifestations include short stature, mild, moderate or severe developmental delay and intellectual disability, variable but mild facial dysmorphism, and epilepsy.
Definition from the Mondo Disease Ontology (MONDO:0015740), read 2026-09-29. CC BY 4.0.
Features
28 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 pinna morphologyHPOHP:0000377
- Very frequent (80% to 99% of cases)
- Attention deficit hyperactivity disorderHPOHP:0007018
- Very frequent (80% to 99% of cases)
- Bilateral cryptorchidismHPOHP:0008689
- Very frequent (80% to 99% of cases)
- BlepharophimosisHPOHP:0000581
- Very frequent (80% to 99% of cases)
- Highly arched eyebrowHPOHP:0002553
- Very frequent (80% to 99% of cases)
- HypotelorismHPOHP:0000601
- Very frequent (80% to 99% of cases)
- Midface retrusionHPOHP:0011800
- Very frequent (80% to 99% of cases)
- Mild intellectual disabilityHPOHP:0001256
- Very frequent (80% to 99% of cases)
- PolyphagiaHPOHP:0002591
- Very frequent (80% to 99% of cases)
- Preauricular skin tagHPOHP:0000384
- Very frequent (80% to 99% of cases)
- Pyloric stenosisHPOHP:0002021
- Very frequent (80% to 99% of cases)
- Sloping foreheadHPOHP:0000340
- Very frequent (80% to 99% of cases)
Show the remaining 16
- TelecanthusHPOHP:0000506
- Very frequent (80% to 99% of cases)
- Thin vermilion borderHPOHP:0000233
- Very frequent (80% to 99% of cases)
- Underdeveloped nasal alaeHPOHP:0000430
- Very frequent (80% to 99% of cases)
- Upslanted palpebral fissureHPOHP:0000582
- Very frequent (80% to 99% of cases)
- Wide nasal bridgeHPOHP:0000431
- Very frequent (80% to 99% of cases)
- Abnormal finger morphologyHPOHP:0001167
- Frequent (30% to 79% of cases)
Where it sits
Other names
4 names
Resolves to: trisomy 18p
- Also called
- Duplication 18pDuplication of the short arm of chromosome 18trisomy of the short arm of chromosome 18trisomy type 18p