MTHFR Gene Testing

What does the MTHFR enzyme do?

It converts dietary folate into 5-MTHF, the active form your body uses to recycle homocysteine into methionine — the backbone of methylation. Methylation touches neurotransmitters, hormone clearance, DNA repair and cardiovascular health, which is why this one enzyme attracts so much attention.

What do C677T and A1298C variants actually mean?

C677T homozygotes (two copies) can have roughly 30% of normal enzyme activity; heterozygotes around 65%. A1298C has milder effects. Reduced activity can raise homocysteine and lower active folate — but many carriers have completely normal function because diet, B12 and riboflavin status compensate.

Why is homocysteine the number that matters?

Because it measures what the variant supposedly breaks. A C677T carrier with homocysteine of 7 has a working methylation cycle regardless of genotype; a non-carrier with homocysteine of 15 has a problem worth addressing. We treat the phenotype — the measured biology — not the genotype in isolation.

This is our standing rule for all genetic findings: DNA sets the hypothesis, labs confirm or dismiss it.

When is action actually warranted?

Elevated homocysteine with a confirmed variant typically responds to methylated folate (5-MTHF), B12, B6 and riboflavin — measured, then retested at 12 weeks. Variants may also inform folate strategy around pregnancy planning, which your physician addresses directly.

What about the sweeping claims online?

MTHFR has become an internet catch-all blamed for everything from anxiety to autoimmunity. The graded evidence supports a real but modest role, centered on homocysteine and folate metabolism. We'll tell you plainly which claims your data supports — and which it doesn't.