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Normal Function
The SLC19A2 gene provides instructions for making a protein called thiamine transporter 1. This protein is located on the surface of cells, where it works to bring vitamin B1 (thiamine) into cells. Thiamine helps the body convert carbohydrates into energy, and it is also essential for the functioning of the heart, muscles, and nervous system. This vitamin must be obtained from food because the body cannot produce thiamine on its own. Many different foods contain thiamine, including whole grains, pasta, fortified breads and cereals, lean meats, fish, and beans.
Health Conditions Related to Genetic Changes
Thiamine-responsive megaloblastic anemia syndrome
Variants (also called mutations) in the SLC19A2 gene have been found to cause thiamine-responsive megaloblastic anemia syndrome, also called TRMA. TRMA is a rare condition that is characterized by hearing loss, diabetes, and a blood disorder called megaloblastic anemia. TRMA is called "thiamine-responsive" because the anemia can be treated with daily doses of thiamine.
Most of the SLC19A2 gene variants that cause TRMA lead to the production of an abnormally short, nonfunctional version of thiamine transporter 1. Other variants change single protein building blocks (amino acids) in thiamine transporter 1, which disrupts the proper folding of the protein or prevents it from reaching the cell surface. All of these variants impair the protein's ability to bring thiamine into the cell. TRMA is treated with daily doses of thiamine because some thiamine can pass into the cell without the help of a transporter when the vitamin is present in large amounts.
It remains unclear exactly how variants in the SLC19A2 gene cause the specific set of features seen in people with TRMA. Research suggests that an alternative transporter made by a different gene is available to transport thiamine in many tissues of the body. However, this alternative transporter may not be as active in the inner ear, the bone marrow (where blood cells are made), and the pancreas (where insulin is made), which would explain why these tissues are affected in people with TRMA.
Other Names for This Gene
- solute carrier family 19 (thiamine transporter), member 2
- TC1
- thiamine transporter 1
- THMD1
- THT1
- THTR1
- TRMA
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
References
- Baron D, Assaraf YG, Cohen N, Aronheim A. Lack of plasma membrane targeting of a G172D mutant thiamine transporter derived from Rogers syndrome family. Mol Med. 2002 Aug;8(8):462-74. Citation on PubMed or Free article on PubMed Central
- Diaz GA, Banikazemi M, Oishi K, Desnick RJ, Gelb BD. Mutations in a new gene encoding a thiamine transporter cause thiamine-responsive megaloblastic anaemia syndrome. Nat Genet. 1999 Jul;22(3):309-12. doi: 10.1038/10385. Citation on PubMed
- Habeb AM, Flanagan SE, Zulali MA, Abdullah MA, Pomahacova R, Boyadzhiev V, Colindres LE, Godoy GV, Vasanthi T, Al Saif R, Setoodeh A, Haghighi A, Haghighi A, Shaalan Y; International Neonatal Diabetes Consortium; Hattersley AT, Ellard S, De Franco E. Pharmacogenomics in diabetes: outcomes of thiamine therapy in TRMA syndrome. Diabetologia. 2018 May;61(5):1027-1036. doi: 10.1007/s00125-018-4554-x. Epub 2018 Feb 15. Citation on PubMed
- Liberman MC, Tartaglini E, Fleming JC, Neufeld EJ. Deletion of SLC19A2, the high affinity thiamine transporter, causes selective inner hair cell loss and an auditory neuropathy phenotype. J Assoc Res Otolaryngol. 2006 Sep;7(3):211-7. doi: 10.1007/s10162-006-0035-x. Epub 2006 Apr 27. Citation on PubMed or Free article on PubMed Central
- Ricketts CJ, Minton JA, Samuel J, Ariyawansa I, Wales JK, Lo IF, Barrett TG. Thiamine-responsive megaloblastic anaemia syndrome: long-term follow-up and mutation analysis of seven families. Acta Paediatr. 2006 Jan;95(1):99-104. doi: 10.1080/08035250500323715. Citation on PubMed
- Sako S, Tsunogai T, Oishi K. Thiamine-Responsive Megaloblastic Anemia Syndrome. 2003 Oct 24 [updated 2022 Jul 28]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2025. Available from http://www.ncbi.nlm.nih.gov/books/NBK1282/ Citation on PubMed
- Subramanian VS, Marchant JS, Parker I, Said HM. Cell biology of the human thiamine transporter-1 (hTHTR1). Intracellular trafficking and membrane targeting mechanisms. J Biol Chem. 2003 Feb 7;278(6):3976-84. doi: 10.1074/jbc.M210717200. Epub 2002 Nov 25. Citation on PubMed
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