The SLC19a1 gene encodes the solute carrier family 19 member 1 protein, transports the vital nutrient folate into an out of cells and plays a role in the intracellular regulation of folate concentrations. SLC19A1 is a major folate transporter and is universally expressed in all tissues of the body.
Folate is required for the production of new cells, through the production and maintenance of DNA and to modulate the expression of genes via DNA methylation. Dietary folate is the precursor molecule that enters the one-carbon cycle, which forms part of the wider methylation cycle. The rate-limiting enzyme in this cycle is the well-researched methylenetetrahydrofolate reductase (MTHFR), and as a result, genetic variations in SLC19A1 are often discussed in conjunction with those of MTHFR.
The T allele is associated with reduced plasma folate. Methotrexate (antifolate drug) uptake was lowest in individuals with CC genotype than those with CT or TT genotypes. It is also important to note the anticoagulants and oral contraceptives can interfere with the uptake of folate from the diet.
Supplementing with bioavailable folate forms such as vitamin B12 is recommended. It is also a good idea to measure your circulating blood serum folate levels and homocysteine levels regularly.