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Phenytoin-induced alterations in craniofacial gene expression
J Gelineau-van Waes1, G D Bennett, R H Finnell
1Department of Veterinary Anatomy and Public Health, Texas A&M University, College Station 77843-4458, USA.
Teratology
|February 16, 1999
Summary
Phenytoin exposure during pregnancy disrupts embryonic development, causing Fetal Hydantoin Syndrome. This study reveals phenytoin alters gene expression, particularly retinoic acid receptors, impacting craniofacial development.
Area of Science:
- Developmental Biology
- Teratology
- Molecular Genetics
Background:
- In utero exposure to phenytoin, an anticonvulsant, causes Fetal Hydantoin Syndrome, characterized by developmental abnormalities.
- The molecular mechanisms underlying phenytoin-induced embryopathy, especially craniofacial malformations, are not fully understood.
Purpose of the Study:
- To investigate the impact of phenytoin exposure on gene expression during critical periods of mouse craniofacial development.
- To identify specific genes and molecular pathways affected by phenytoin that may contribute to Fetal Hydantoin Syndrome.
Main Methods:
- Pregnant SWV mice received phenytoin from gestational day 6.5.
- Craniofacial tissues from exposed and control embryos were analyzed at various developmental time points.
- Gene expression levels of 36 candidate genes were quantitatively assessed using in situ transcription and reverse Northern blot hybridization.
Main Results:
- Phenytoin exposure significantly altered the expression of several genes during craniofacial morphogenesis.
- Increased expression of retinoic acid receptors (RAR alpha, beta, gamma) was observed.
- Elevated gene expression of laminin beta 1 and growth factors (IGF-2, TGF alpha, TGF beta 1) was noted in phenytoin-exposed embryos.
Conclusions:
- Phenytoin-induced alterations in RAR isoform expression may disrupt downstream gene regulation essential for normal craniofacial development.
- Coordinated changes in gene expression during critical developmental windows likely contribute to the dysmorphogenesis seen in Fetal Hydantoin Syndrome.
- This study provides insights into the molecular pathogenesis of phenytoin embryopathy, highlighting the role of retinoic acid signaling pathways.