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A fragile site at 10q23 (FRA10A) in a phenytoin‐exposed fetus: a case report and review of the literature
Author(s) -
Morel Chantal F.,
Duncan Alessandra M. V.,
Désilets Valérie
Publication year - 2005
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.1134
Subject(s) - phenytoin , fetus , medicine , epilepsy , pregnancy , genetics , biology , psychiatry
Objective To report fragility at 10q23.3 in a fetus exposed to phenytoin during pregnancy. Review of the literature. Methods Amniocytes were cultured in A10 (WISENT) culture medium. Molecular polymorphism studies of MTHFR gene using PCR were performed on fetal tissues. Results The fragile site was expressed in all 22 amniocyte colonies analyzed. Analysis of fetal blood showed 46,XX[98]/46,XX,fra(10)(q23.3)[3]/46,XX,del(10)(q23.3) [1]. Molecular studies of the MTHFR (methylenetetrahydrofolate reductase) gene identified a compound heterozygote genotype for two polymorphisms, 677C>T and 1298A>C. Conclusion The fragility at 10q23.3 is unlikely to be due to culture condition–induced folic acid deficiency (medium contains folate). It is possible that this finding represents a previously undescribed folic acid–insensitive fragile site in the region of 10q23.3. Alternatively, the fetal cells may have had decreased folate metabolism, and the fragile site was the known folate‐sensitive FRA10A. Since phenytoin has been shown to decrease MTHFR activity in mice, we postulate that the fragile site at 10q23.3 in this fetus may have arisen secondary to a combination of the polymorphisms in MTHFR and exposure to this drug, and is indeed FRA10A. Copyright © 2005 John Wiley & Sons, Ltd.