Snips about SNPs: MTHFR

The MTHFR gene codes for the enzyme that converts folate into the form that your body needs in the methylation cycle (methylfolate). There are two main SNPs that have been shown to decrease the efficiency of the MTHFR enzyme.  For both of these, it is important to make sure you get plenty of folate-rich foods in your diet. Good sources of folate include dark leafy greens, legumes, broccoli, and liver.

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Check your genetic data for rs1801133 (23andMe v4, v5; AncestryDNA):

  • G/G: typical
  • A/G: one copy of MTHFR C677T allele (heterozygous), decreased by 40%
  • A/A: two copies of MTHFR C677T (homozygous), decreased by 70 – 80%

Members: Your genotype for rs1801133 is .


Check your genetic data for rs1801131 (23andMe v4, v5; AncestryDNA):

  • T/T: typical
  • G/T: one copy of MTHFR A1298C (heterozygous),  decreased enzyme
  • G/G: two copies of MTHFR A1298C (homozygous), decreased enzyme

Members: Your genotype for rs1801131 is .

Learn more about MTHFR and steps that you can take to mitigate the impact.


*SNP stands for Single Nucleotide Polymorphism, which is when one of the nucleotide bases (the A, C, G, or Ts) is replaced by a different nucleotide base in a gene. 

Want more quick bits about your genes? Read through all the Snips about SNPs