G
Genetic Archaeology
GENETIC ARCHAEOLOGY // PROFILE

MTHFR

Methylenetetrahydrofolate Reductase

CHR 1
1p36.22

Overview

MTHFR encodes an enzyme that plays an important role in folate metabolism and homocysteine regulation.

📍 Chromosomal Position

1p36.22 (Chromosome 1)

🧬 Gene Category

Vitamins

🔬 Inheritance

Autosomal recessive

📊 Prevalence

30-40% heterozygous

Function & Significance

The MTHFR enzyme catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, the active form of folate. This is vital for DNA synthesis, repair, and methylation.

🔬 Methylation Cycle

MTHFR is essential for:

  • DNA methylation (gene regulation)
  • Homocysteine breakdown
  • Neurotransmitter synthesis
  • Detoxification processes

🧬 Relevant SNPs

The two most common MTHFR variants:

rs1801133
1:11856378
Allele 1

C

/

Allele 2

T

Significance: C677T variant – reduces enzyme activity by 30-70%. Leads to increased homocysteine. TT genotype: higher folate requirement.

rs1801131
1:11854476
Allele 1

A

/

Allele 2

C

Significance: A1298C variant – milder effect on enzyme activity. Compound heterozygotes (C677T + A1298C) have an increased risk.

💊 Recommendations for MTHFR Variants

  • Folate Supplementation: 400-800 µg daily
  • Methylfolate: Active form for TT genotype
  • Vitamin B12: Supports methylation
  • Vitamin B6: Homocysteine breakdown
  • Homocysteine Monitoring: Regular blood tests

📚 Data Sources

The information on this page is based on the following scientific sources:

  • OMIM: #607093 – Online Mendelian Inheritance in Man
  • dbSNP: rs1801133, rs1801131 – SNP Database (NCBI)
  • ClinVar: Clinical Variant Database (NCBI)
  • PubMed: Folate metabolism research
  • NIH: Homocysteine & Methylation Studies

Last Update: February 2026

Associated Risks

  • ❤️ Cardiovascular Diseases

    Increased homocysteine = risk factor

  • 🤰 Neural Tube Defects

    Important: Folic acid before pregnancy!

  • 🩸 Thrombosis

    In homozygous carriers

Biological Function

The MTHFR enzyme catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, the active form of folate. This is important for DNA synthesis, repair, and methylation. The common C677T variant leads to reduced enzyme activity.

Associated Conditions

Hyperhomocysteinemia Increased risk for cardiovascular diseases Neural tube defects (in folate deficiency) Thrombosis (in homozygous carriers)
Molecular Analysis

Analyzed Markers

rs1801133 Risk Factor
Pos: 1:11856378 | Alleles: C/T

C677T variant - Reduced enzyme activity, elevated homocysteine

rs1801131 Risk Factor
Pos: 1:11854476 | Alleles: A/C

A1298C variant - Milder effect on enzyme activity