MTHFR: A1298C

rs1801131 · Methylation & Folate Metabolism

The MTHFR A1298C variant is the second common MTHFR mutation. While less impactful than C677T alone, compound heterozygosity (carrying both) can significantly affect methylation.

What This SNP Does

A1298C (Glu429Ala) affects MTHFR enzyme function through a different mechanism than C677T. On its own, A1298C has a modest effect (~10-20% reduced activity for heterozygous). However, individuals who carry both A1298C and C677T (compound heterozygous) may have methylation impairment comparable to C677T homozygous status. This variant also influences BH4 (tetrahydrobiopterin) recycling, which affects neurotransmitter synthesis.

Genotype Meanings

Genotype	Status	What It Means
AA	Normal	No reduction from this variant. (Check rs1801133 for C677T status.)
AC	Carrier	~10-20% reduced activity. Minimal impact alone, but important if also carrying C677T.
CC	Homozygous	More significant reduction. May affect BH4 recycling and neurotransmitter synthesis.

What You Can Do

The critical question is whether you also carry C677T (rs1801133). Compound heterozygous status (CT + AC) may warrant methylfolate supplementation. A full report checks both variants together for accurate methylation risk assessment.

This information is for educational purposes only and is not medical advice. Always consult a qualified healthcare provider before making health decisions based on genetic data. Genome Decoder does not diagnose, treat, or prevent any disease.