Skip to content
Use your HSA or FSA funds

Gene

MTRR

5-methyltetrahydrofolate-homocysteine methyltransferase reductase

Summary

Cytogenetic location
5p15.31
Coordinates
Chromosome 5: 7,869,148–7,901,113 (GRCh38)
Exons
15 exons across 32 kb
Protein
698 amino acids
Inheritance
Autosomal recessive
Also known as
cblE
MANE Select transcript
ENST00000440940.7NM_002454.3
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated report relevant to this gene

  • Homocystinuria & Cobalamin Disorders

    • HomocystinuriaAutosomal recessive

      Includes classic homocystinuria due to CBS deficiency, severe MTHFR deficiency and the combined and remethylation cobalamin disorders, which can cause lens dislocation, blood clots, skeletal changes, anaemia and developmental problems.

      • ClinGen rates the link definitive
      • 5 GenCC submitters rate it definitive or strong
      What knowing changes

      Knowing allows treatment with vitamin B6, B12, folate, betaine and diet as appropriate, which can prevent lens dislocation, thrombosis and other complications.

    • Inborn Disorders of Cobalamin Metabolism and TransportAutosomal recessive

      Includes defects in vitamin B12 absorption and transport such as Imerslund-Gräsbeck syndrome (CUBN, AMN), intrinsic factor deficiency (CBLIF) and transcobalamin II deficiency (TCN2), as well as intracellular cobalamin processing defects, which can cause megaloblastic anaemia, nerve damage and failure to thrive.

      • ClinGen rates the link definitive
      • 5 GenCC submitters rate it definitive or strong
      What knowing changes

      Knowing allows lifelong vitamin B12 injections or other cobalamin treatment, which can prevent anaemia and neurological damage.

Inheritance

Autosomal recessive
It takes a changed copy from each parent. With one, you are a carrier and usually unaffected; when both parents are carriers, each child has a one-in-four chance of inheriting two.

How MTRR is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
Chromosome 5, with a bracket where MTRR sits. MTRR and 3 genes near it on chromosome 5, from 7,385,131 to 8,385,130.Chromosome 55p15.31p15.33p15.32p15.31p15.2p15.1p14.3p14.2p14.1p13.3p13.2p13.1p12p11q11.1q11.2q12.1q12.2q12.3q13.1q13.2q13.3q14.1q14.2q14.3q15q21.1q21.2q21.3q22.1q22.2q22.3q23.1q23.2q23.3q31.1q31.2q31.3q32q33.1q33.2q33.3q34q35.1q35.2q35.37.4 Mb7.6 Mb7.8 Mb8 Mb8.2 MbADCY2: 7,395,681–7,830,638, forward strandADCY2CFAP90: 7,830,378–7,851,677, reverse strandCFAP90FASTKD3: 7,858,812–7,869,060, reverse strandFASTKD3MTRR: 7,869,148–7,901,113, forward strandMTRRDiagram of MTRR: 15 exons on the forward strand of chromosome 5Exon 2: 4 known disease-causing sitesExon 3: 12 known disease-causing sitesExon 4: 12 known disease-causing sitesExon 5: 26 known disease-causing sitesExon 6: 5 known disease-causing sitesExon 7: 8 known disease-causing sitesExon 8: 3 known disease-causing sitesExon 9: 11 known disease-causing sitesExon 10: 4 known disease-causing sitesExon 11: 13 known disease-causing sitesExon 12: 9 known disease-causing sitesExon 13: 4 known disease-causing sitesExon 14: 4 known disease-causing sitesExon 1: 7,869,148–7,869,215, 68 basesExon 2: 7,870,770–7,870,923, 154 basesExon 3: 7,873,373–7,873,526, 154 basesExon 4: 7,875,258–7,875,375, 118 basesExon 5: 7,877,944–7,878,322, 379 basesExon 6: 7,883,155–7,883,277, 123 basesExon 7: 7,885,701–7,885,854, 154 basesExon 8: 7,886,615–7,886,703, 89 basesExon 9: 7,889,095–7,889,275, 181 basesExon 10: 7,891,372–7,891,414, 43 basesExon 11: 7,892,727–7,892,913, 187 basesExon 12: 7,895,734–7,895,852, 119 basesExon 13: 7,896,864–7,896,956, 93 basesExon 14: 7,897,065–7,897,247, 183 basesExon 15: 7,899,914–7,901,113, 1,200 bases12468101214155′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 3.2 kb of the gene's 32 kb; 2,097 of those bases code for the protein.

How a genome test reads MTRR

145

positions in MTRR where ClinVar classes a change as pathogenic or likely pathogenic

None of them falls in a region short reads find hard.

A whole genome covers all 32 kb of MTRR, introns included, not only the 3.2 kb of exons.

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
  • The ACMG secondary findings list, SF v3.2.
  • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

Cite this page

APA

Dante Labs. (n.d.). MTRR gene: 5-methyltetrahydrofolate-homocysteine methyltransferase reductase. Retrieved 17 October 2026, from https://dantelabs.com/genes/mtrr

Vancouver

Dante Labs. MTRR gene: 5-methyltetrahydrofolate-homocysteine methyltransferase reductase [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/mtrr

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test