The influence of 5,10 methylenetetrahydrofolate reductase genotypes on enzyme activity in placental tissue.
OBJECTIVE
To study the effects of heterozygosity and homozygosity for the C677T mutation of the 5,10 methylenetetrahydrofolate reductase (MTHFR) gene on the activity of this enzyme in placental tissue from pregnancies not affected by neural tube defect.


METHODS
Placental tissue was genotyped for the C677T variants of MTHFR. Total enzyme activity and residual activity after heating to 46 degrees C for 5 minutes was then measured.


METHODS
A teaching hospital.


METHODS
Placental samples (n = 200), one from each of 200 uncomplicated term deliveries.


METHODS
Total and residual enzyme activity for MTHFR.


RESULTS
Placentae heterozygous for the C677T mutation of the MTHFR gene had significantly lower total enzyme activity than those without the mutation; the lowest activity occurred in homozygotes for the mutation. The same pattern was seen in relation to enzyme activity after heating.


CONCLUSIONS
This study demonstrates that reduced enzyme activity is associated with the C677T variant of MTHFR in placental tissue. This is an important metabolic step in folic acid metabolism and pro-
Daly
S F
SF
Royal College of Surgeons, Coombe Women's Hospital, Dublin, Ireland.
Molloy
A M
AM
Mills
J L
JL
Lee
Y J
YJ
Conley
M
M
Kirke
P N
PN
Weir
D G
DG
Scott
J M
JM
D015415:Biomarkers / Q000097:blood; D005260:Female; D005838:Genotype; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000378:metabolism*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy
D015415:Biomarkers; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2)