Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Methotrexate is an antifolate: it blocks the enzyme dihydrofolate reductase, which cells need to use folate for making DNA. At high doses it is a chemotherapy medicine for leukaemia, lymphoma and other cancers; at low weekly doses it calms the immune system and is a mainstay treatment for rheumatoid arthritis, psoriasis and other inflammatory conditions. It is sold as Trexall, Otrexup and other names; MTX is its short name.
Methotrexate touches many genes of the folate pathway, and over 400 studies have looked at them. The most studied are MTHFR, whose common variant rs1801133 (C677T) lowers the enzyme's activity, linked in some studies to more side effects; SLC19A1, the carrier that takes methotrexate into cells; ATIC; and SLCO1B1 and ABCG2, which affect how fast high-dose methotrexate is cleared. The findings are often inconsistent between studies, and there is no CPIC or DPWG guideline.
Every published finding on gene variants and Methotrexate. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
MTHFR rs1801133: Level 2A · replicated. Toxicity: Acute lymphoblastic leukemia, Drug Toxicity, Leukopenia, Lymphoma, Mucositis, Myelosuppression, Neoplasms, Neutropenia, Osteosarcoma, Primary central nervous system lymphoma, Thrombocytopenia, Toxic liver disease. 32.
MTHFR rs1801133: Level 2A · replicated. Toxicity: Arthritis, Psoriatic, Drug Toxicity, Juvenile Rheumatoid Arthritis, Rheumatoid arthritis. 12.
SLC19A1 rs1051266: Level 2A · replicated. Efficacy: Rheumatoid arthritis. 9.
ATIC rs4673993: Level 2B · replicated. Efficacy: Rheumatoid arthritis. 5.
Studies of how quickly the body processes this medication.
Studies of how well it worked in people carrying a variant.
Studies of how much of the drug people needed or tolerated.
Studies of side effects in people carrying a variant.
Studies that do not fall into the groups above.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
ReadYourDNA provides educational interpretation of DNA data you already have. It is not diagnostic, not a substitute for professional medical advice, diagnosis, or treatment, and is not intended to diagnose, treat, cure, or prevent any disease. Talk to a clinician before acting on any result.
Raw DNA Data Reports for 23andMe & AncestryDNA · About ReadYourDNA · FAQ · Methodology & Science · Pricing · Support and complaints · Legal & Contact · Health Traits · Pharmacogenomics · Carrier Status · Variant Explorer · The Human Karyotype · Privacy Policy · Terms of Service · Accessibility · Consumer Health Data Privacy · Your Privacy Choices · Editorial Standards · Your Data, Checkable · Sample Report · ReadYourDNA and Promethease compared · What is inside a 23andMe raw data file · What is inside an AncestryDNA raw data file · What a chatbot can and cannot do with your raw DNA file · Where a raw DNA file can still be uploaded in 2026
Written, maintained and operated by Martin Pechhacker, sole proprietor, Vienna, Austria. Trade register GISA 40064420. support@readyourdna.com