Polymorphism for mutation of cytosine to thymine at location 677 in the methylenetetrahydrofolate reductase gene is associated with recurrent early fetal loss.
OBJECTIVE
This study was undertaken to determine whether a cytosine to thymine mutation at nucleotide 677 in the gene encoding for methylenetetrahydrofolate reductase is associated with particular subtypes of recurrent unexplained spontaneous abortion.


METHODS
The prevalences of cytosine to thymine mutation at nucleotide 677 in the gene encoding for methylenetetrahydrofolate reductase among 41 patients with recurrent unexplained spontaneous abortions and among 18 healthy control subjects were determined with polymerase chain reaction.


RESULTS
Homozygosity and heterozygosity for the cytosine to thymine mutation at nucleotide 677 in the gene encoding for methylenetetrahydrofolate reductase were observed at nonsignificantly different rates among patients and control subjects (9% and 48% versus 22% and 38%, respectively, P <.95). Among patients with recurrent unexplained spontaneous abortions both homozygosity and heterozygosity were associated with significantly increased prevalence of recurrent early fetal loss rather than with repeated anembryonic gestations (P <.0001).


CONCLUSIONS
The observation that polymorphism for the cytosine to thymine mutation at nucleotide 677 in the gene encoding for methylenetetrahydrofolate reductase is associated with repeated early fetal losses rather than with anembryonic gestations strengthens the argument for the role of hypercoagulability and abnormal uteroplacental vasculature in recurrent spontaneous abortion.
Lissak
A
A
Department of Obstetrics and Gynecology, Lady Davis Carmel Medical Center, Haifa, Israel.
Sharon
A
A
Fruchter
O
O
Kassel
A
A
Sanderovitz
J
J
Abramovici
H
H
D000026:Abortion, Habitual / Q000235:genetics*; D000328:Adult; D016022:Case-Control Studies; D003597:Cytosine Nucleotides / Q000032:analysis*; D005260:Female; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D009154:Mutation; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011247:Pregnancy; D013942:Thymine Nucleotides / Q000032:analysis*; D013997:Time Factors
D003597:Cytosine Nucleotides; D013942:Thymine Nucleotides; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2)