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Start free with EleplanFetal hydantoin syndrome
ORPHA:1912Malformation syndrome
Also called Fetal dihydantoin syndrome · Phenytoin embryofetopathy
What it is
A drug-related embryofetopathy that can occur when an embryo/fetus is exposed to the anticonvulsant drug phenytoin, characterized by distinct craniofacial anomalies (hypertelorism and epicanthal folds, short nose and deep nasal bridge, malformed and low set ears, short neck) as well as hypoplastic distal phalanges and underdevelopment of nails of fingers and toes, prenatal and postnatal growth retardation, and neurological impairment (at a 2-3 times higher risk than that of the general population) including cognitive deficits and motor developmental delay. Less commonly, microcephaly, ocular defects, oral clefts, umbilical and inguinal hernias, hypospadias and cardiac anomalies have also been reported.
Key facts
- Age of onset
- Antenatal, Neonatal
- Inheritance
- Not applicable
- Classified as
- Malformation syndrome
Signs and symptoms
Very common80–99%
6Common30–79%
20- Abnormality of the fontanelles or cranial sutures
- Bifid scrotum
- Coarse hair
- Epicanthus
- Everted lower lip vermilion
- Global developmental delay
- Hernia
- Hypertelorism
- Hypoplastic fingernail
- Intrauterine growth retardation
- Low posterior hairline
- Microcephaly
- Ptosis
- Short distal phalanx of finger
- Short stature
- Strabismus
- Thickened nuchal skin fold
- Triphalangeal thumb
- Wide intermamillary distance
- Wide mouth
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
ICD-10 codes
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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