Thiopurine S-Methyltransferase

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TPMT or TPMTD or Thiopurine S-Methyltransferase or Thiopurine Methyltransferase refers to either a gene or the enzyme encoded by it.[1]

Function[edit | edit source]

TPMT has a role in the function of the immune system.

Thiopurine methyltransferase deficiency[edit | edit source]

TPMT deficiency is a genetic condition that means that the enzymes that help process thiopurine drugs have reduced activity.[2] If people with TPMT deficiency take thiopurine drugs, they are at inceased risk of bone marrow damage.[2]

Thiopurine genetic testing[edit | edit source]

TPMT genetic testing aims to improve climical outcomes and reduce harm in people with TPMT deficiency.[3]

Drug responses[edit | edit source]

Thiopurines are relatively common drugs, but thiopurine methyltransferase deficiency studies have found that 1 in 300 people have no thiopurine methyltransferase enzyme activity, and 11% have reduced activity.[4][5]

Thiopurines (drugs)[edit | edit source]

Thiopurine drugs suppress immune system, they include:

  • 6-thioguanine
  • 6-mercaptopurine
  • azathioprine

Thiopurine drugs are used to treat:

ME/CFS[edit | edit source]

Genetic studies of ME/CFS patients have not so far identified any TPMT genes as possibly associated with ME/CFS.[6]

Thiopurine drugs have not been suggested as potentially useful for ME/CFS, and there is no guidance to avoid them.[7][8][9]

See also[edit | edit source]

Learn more[edit | edit source]

References[edit | edit source]

  1. "TPMT Gene - Thiopurine S-Methyltransferase Protein Coding". Gene cards. Retrieved April 7, 2022.
  2. 2.0 2.1 2.2 "Thiopurine S-methyltransferase deficiency". Medline Plus. Retrieved April 8, 2022.
  3. Royal College of Physicians; British Pharmacological Society (2022), Personalised prescribing: using pharmacogenomics to improve patient outcomes. Report of a working party., London: RCP and BPS
  4. Lennard, Lynne (April 2014). "Implementation of TPMT testing: TPMT testing". British Journal of Clinical Pharmacology. 77 (4): 704–714. doi:10.1111/bcp.12226. PMC 3971986. PMID 23962279.
  5. "TPMT gene". Medline Plus. Retrieved April 8, 2022.
  6. Dibble, Joshua J; McGrath, Simon J; Ponting, Chris P (August 3, 2020). "Genetic risk factors of ME/CFS: a critical review". Human Molecular Genetics. 29 (R1): R117–R124. doi:10.1093/hmg/ddaa169. ISSN 0964-6906. PMC 7530519. PMID 32744306.
  7. Carruthers, Bruce M.; Jain, Anil Kumar; De Meirleir, Kenny L.; Peterson, Daniel L.; Klimas, Nancy G.; Lerner, A. Martin; Bested, Alison C.; Flor-Henry, Pierre; Joshi, Pradip; Powles, AC Peter; Sherkey, Jeffrey A.; van de Sande, Marjorie I. (2003), "Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Clinical Working Case Definition, Diagnostic and Treatment Protocols" (PDF), Journal of Chronic Fatigue Syndrome, 11 (2): 7–115, doi:10.1300/J092v11n01_02
  8. Carruthers, BM; van de Sande, MI; De Meirleir, KL; Klimas, NG; Broderick, G; Mitchell, T; Staines, D; Powles, ACP; Speight, N; Vallings, R; Bateman, L; Bell, DS; Carlo-Stella, N; Chia, J; Darragh, A; Gerken, A; Jo, D; Lewis, DP; Light, AR; Light, KC; Marshall-Gradisnik, S; McLaren-Howard, J; Mena, I; Miwa, K; Murovska, M; Stevens, SR (2012), Myalgic encephalomyelitis: Adult & Paediatric: International Consensus Primer for Medical Practitioners (PDF), ISBN 978-0-9739335-3-6
  9. NICE Guideline Development Group (October 29, 2021). "Myalgic Encephalomyelitis (or Encephalopathy)/Chronic Fatigue Syndrome:diagnosis and management. NICE guideline". National Institute for Health and Care Excellence.