Does MTHFR C677T homozygosity significantly increase thrombosis risk?

Modern evidence shows minimal clinically significant VTE risk for isolated MTHFR variants; 2020 ISTH guidelines recommend against MTHFR testing for VTE risk stratification.

What folate supplement is preferred for MTHFR C677T?

L-methylfolate (5-MTHF) bypasses the reduced enzyme activity; recommended over folic acid in homozygotes (TT/TT); 400-800 mcg/day of methylfolate is standard supplementation.

What homocysteine level from MTHFR TT genotype warrants supplementation?

Total homocysteine >12 μmol/L with MTHFR TT genotype warrants B12 (methylcobalamin) + folate supplementation; target homocysteine <10 μmol/L; reduce cardiovascular and neural tube defect risk.

Is MTHFR testing recommended in pregnancy?

MTHFR testing in pregnancy is not routinely recommended; standard folate supplementation (400-800 mcg/day) is adequate for most; high-dose folate (4 mg/day) is recommended only after a prior NTD-affected pregnancy.

What psychiatric conditions are associated with MTHFR variants?

Weak associations with depression and schizophrenia are described; methylfolate augmentation may benefit MTHFR-positive patients with inadequate SSRI response; evidence base is modest.

MTHFR Variant Thrombosis and Folate Supplementation Calculator

Calculates thrombosis risk in MTHFR C677T and A1298C variants, homocysteine target levels, and optimal folate/B12 supplementation dosing for mild hyperhomocysteinemia management.

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Frequently Asked Questions

Does MTHFR C677T homozygosity significantly increase thrombosis risk?

What folate supplement is preferred for MTHFR C677T?

What homocysteine level from MTHFR TT genotype warrants supplementation?

Is MTHFR testing recommended in pregnancy?

What psychiatric conditions are associated with MTHFR variants?