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Genetic and Rare Diseases Information Center (GARD)

Fetal hydantoin syndrome

Other Names for this Disease
  • Dilantin Embryopathy
  • Phenytoin Embryopathy
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What are the signs and symptoms of Fetal hydantoin syndrome?

There is a wide range in the nature and severity of characteristics associated with fetal hydantoin syndrome. Of infants born to women who used phenytoin during pregnancy, 10-30% are reported to show some of the characteristics associated with this syndrome. Few infants exposed only to phenytoin have all of the characteristic that have been reported.[1]

Children with this condition may be small at birth, with increased hair on the body and face, and with poorly developed fingernails and toenails.[2] They may also have poor muscle tone.[2] Facial features that may be present with this syndrome include a flat bridge of the nose; an underdeveloped vertical groove in the center of the upper lip (philtrum); a large mouth; and malformed ears. Features specific to the eyes may include down-slanted eyes; widely spaced eyes (hypertelorism); crossed eyes (strabismus); drooping eyelids (ptosis); and/or epicanthal folds (skin folds of the eyelid covering the inner corner of the eye). Other features that have been reported include a short or webbed neck and low-set hair line.[2][3] Growth deficiencies may include underdeveloped fingers and/or toes, malformed nails, as well as finger-like thumbs.[2]

These features are often associated with growth delay and varying degrees of developmental delay. The risk for an affected child to be neurologically impaired is estimated at 1 to 11 % (two to three times higher than for the general population). The risk of cleft lip and/or palate and heart defects is estimated to be about five times higher among exposed infants. Some case reports have suggested an increased risk for the occurrence of benign (noncancerous) or malignant (cancerous) tumors, such as neuroblastoma or other neonatal tumors (ependymoma, ectodermal tumors, Wilms tumor).[3]
Last updated: 8/10/2011

The Human Phenotype Ontology provides the following list of signs and symptoms for Fetal hydantoin syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.

Signs and Symptoms Approximate number of patients (when available)
Abnormal dermatoglyphics 90%
Depressed nasal ridge 90%
Hearing abnormality 90%
Low-set, posteriorly rotated ears 90%
Short nose 90%
Abnormality of the fontanelles or cranial sutures 50%
Abnormality of the nipple 50%
Anonychia 50%
Bifid scrotum 50%
Brachydactyly syndrome 50%
Coarse hair 50%
Cognitive impairment 50%
Epicanthus 50%
Everted lower lip vermilion 50%
Hernia 50%
Hypertelorism 50%
Intrauterine growth retardation 50%
Low posterior hairline 50%
Microcephaly 50%
Ptosis 50%
Short stature 50%
Strabismus 50%
Thickened nuchal skin fold 50%
Triphalangeal thumb 50%
Wide mouth 50%
Abnormality of the cardiovascular system 7.5%
Cryptorchidism 7.5%
Neoplasm 7.5%

Last updated: 7/1/2016

The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.

The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.

Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.

  1. Aaron B Caughey. Seizure Disorders in Pregnancy. eMedicine. June 28, 2011; Accessed 8/10/2011.
  2. Fetal Hydantoin Syndrome. NORD. April 25, 2008; Accessed 8/9/2011.
  3. E. Robert-Gnansia. Fetal hydantoin syndrome. Orphanet. February 2006; Accessed 8/10/2011.

Other Names for this Disease
  • Dilantin Embryopathy
  • Phenytoin Embryopathy
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.