Fetal hydantoin syndrome

Philippe Jeanty, MD, PhD Sandra R Silva, MD

Definition:  Effects due to maternal exposure to hydantoin anticonvulsant.

Synonyms: Dilantin, Phenytoin and a few other similar anticonvulsants are also included.

Incidence:  7-10% of exposed infants.

Etiology: Alteration of enzymatic pathways[1],[2]. Sibs exposed to similar amount have been affected to different degrees.

Recurrence risk: None

Diagnosis: Growth retardation, microcephaly, hypoplasia of the distal phalanx of the fingers and toes, nail hypoplasia, typical facial appearance with a low nasal bridge, hirsutism and cleft-lip/palate, rib anomalies and occasionally cardiac and genito-urinary anomalies[3],[4],[5].

Genetic anomaly: None

Associated anomalies: None

Differential diagnosis: Other causes of growth restriction and cardiac anomalies, thus a TORCH titer and karyotype should be obtained.

Prognosis: Dependent on the severity of the case.

Management: Switch the mother to a different medication if possible. Some prenatal testing might be possible[6].


[1] Buehler BA, Rao V, Finnell RH Biochemical and molecular teratology of fetal hydantoin syndrome. Neurol Clin 1994 Nov;12(4):741-8

[2] Finnell RH, Buehler BA, Kerr BM, Ager PL, Levy RH Clinical and experimental studies linking oxidative metabolism to phenytoin-induced teratogenesis. Neurology 1992 Apr;42(4 Suppl 5):25-31

[3] Sabry MA, Farag TI Hand anomalies in fetal-hydantoin syndrome: from nail/phalangeal hypoplasia to unilateral acheiria. Am J Med Genet 1996 Apr 24;62(4):410-2

[4] Ozkinay F, Yenigun A, Kantar M, Ozkinay C, Avanoglu A, Ulman I Two siblings with fetal hydantoin syndrome. Turk J Pediatr 1998 Apr-Jun;40(2):273-8

[5] Adams J, Vorhees CV, Middaugh LD Developmental neurotoxicity of anticonvulsants: human and animal evidence on phenytoin. Neurotoxicol Teratol 1990 May-Jun;12(3):203-14

[6] Buehler BA, Delimont D, van Waes M, Finnell RH Prenatal prediction of risk of the fetal hydantoin syndrome. N Engl J Med 1990 May 31;322(22):1567-72

Discussion Board

Start a discussion about this article
Add bookmark Bookmarked