It Is a Transport Gene
SLC19A1 helps encode a carrier protein. It is different from enzymes such as MTHFR that chemically modify folate-related compounds.
SLC19A1 gene guide for US test customers
SLC19A1 Gene and Methylation: Folate Transport Explained
Learn how the SLC19A1 gene helps move reduced folates into cells, why intracellular folate matters to one-carbon and methylation-related pathways, and what an SLC19A1 variant can—and cannot—tell you.
What does the SLC19A1 gene do?
SLC19A1 provides instructions for the reduced folate carrier, a membrane transport protein that helps move folates across cell membranes and supports the folate-dependent processes taking place inside cells.
A transporter, not a methylation enzyme
SLC19A1 helps folate enter cells. It does not directly perform a methylation reaction or measure your current folate level.
Reduced folate carrier
SLC19A1 encodes a membrane protein involved in transporting folates into cells.
Part of a wider pathway
Folate transport connects with one-carbon metabolism, DNA synthesis and methyl-group transfer.
Educational genetic result
A detected variant does not diagnose folate deficiency or impaired transport.
The SLC19A1 pathway in plain language
How Folate Moves from Outside a Cell to Folate-Dependent Reactions
Folate must be available inside cells before it can support many one-carbon reactions. SLC19A1 helps transport reduced forms of folate across the cell membrane.
Reduced Folate Outside the Cell
Folate-related compounds are present outside the cell and need a route across the cell membrane.
SLC19A1 Reduced Folate Carrier
The carrier helps transport reduced folates across the plasma membrane.
Folate Available Inside the Cell
Intracellular folate can participate in folate-dependent one-carbon and nucleotide-related processes.
This is a simplified educational diagram. A consumer genetic result does not measure how much folate is entering your cells, how quickly the transporter is working or your current folate status.
Transport is different from intake
A gene result cannot tell you how much folate you eat, absorb from your digestive system or currently have in your blood or cells.
Why people research SLC19A1
Why the SLC19A1 Gene Appears in Methylation Reports
SLC19A1 often appears in broader methylation panels because folate availability inside cells supports reactions connected with DNA synthesis, amino-acid metabolism and the production of methyl donors.
SLC19A1 is therefore connected to methylation indirectly through folate transport. It is not the enzyme that converts folate into another form, recycles homocysteine or transfers a methyl group.
- SLC19A1 is the gene that encodes the reduced folate carrier.
- The carrier helps regulate intracellular folate availability.
- A reported SNP is an inherited DNA difference, not a folate measurement.
- A common variant is not automatically harmful or disease-causing.
- Diet, medications, health conditions and other genes can affect the wider context.
Learn how ordinary variants differ from clinically significant changes on the Genetic Variants vs Mutations page. For genotype terminology, read SNPs and Methylation.
SLC19A1 essentials
Four Points to Understand Before Reading Your Result
It Is Located on Chromosome 21
The human SLC19A1 gene is located at chromosome region 21q22.3 and is expressed in many tissues.
A Variant Is Not a Folate Test
A genotype cannot confirm whether your serum, red-blood-cell or intracellular folate level is low, normal or high.
One Result Is Not the Whole Pathway
Folate metabolism depends on several transporters, enzymes, nutrients and cellular processes—not one SLC19A1 marker alone.
Set realistic expectations
What an SLC19A1 Genetic Result Can and Cannot Tell You
A useful report identifies the variant and provides pathway context without claiming to measure your current folate transport, nutrient status or health condition.
An SLC19A1 Report Can Help You
- Identify the SLC19A1 variant or genotype reviewed.
- Understand the gene’s role as a reduced folate transporter.
- See how folate transport relates to wider one-carbon pathways.
- Compare SLC19A1 with enzymes and transporters included in the same panel.
- Prepare better questions about clinical testing or professional interpretation.
An SLC19A1 Report Cannot Confirm
- Your current reduced folate carrier activity.
- Your present blood, red-blood-cell or intracellular folate level.
- That you cannot absorb or use folate normally.
- The cause of fatigue, anemia, brain fog or another symptom.
- Which folate form, supplement, medication or dosage is appropriate for you.
An important clinical distinction
A Common SLC19A1 SNP Is Not the Same as Folate Transport Deficiency
Search results can place common consumer-test variants beside information about a rare inherited disorder. These are not interchangeable findings.
SNP or Polymorphism
A consumer methylation report may identify a common SLC19A1 variant. The result may have limited, uncertain or context-dependent significance and does not diagnose a disorder.
Its meaning depends on the exact variant, scientific evidence, laboratory method and the rest of your genetic and health information.
SLC19A1-Related Folate Transport Deficiency
This rare disorder is associated with pathogenic variants affecting both copies of SLC19A1 and requires clinical genetic evaluation, appropriate testing and professional diagnosis.
Seeing one common SNP in an educational report does not mean that you have this condition or carry one of its known pathogenic variants.
Use a broader testing perspective
Why SLC19A1 Should Be Reviewed with Other Genes
SLC19A1 helps transport folate into cells, but other genes influence folate conversion, vitamin B12-dependent reactions, homocysteine recycling and related methylation processes.
A broader panel can help distinguish transport genes from enzymes and show where each result fits. It still cannot measure your current pathway activity.
Look beyond one transporter
Folate-related pathways involve transport, conversion, recycling and methyl-group transfer. Each step may involve different genes.
Practical testing access across the US
Searching for an SLC19A1 Gene Test Near You?
You usually do not need to locate a specialist SLC19A1 collection clinic in your city. If the gene is included in an at-home methylation panel, you can complete the cheek-swab collection from your own address and return it for processing.
The collection process is similar across large metropolitan areas, suburbs, smaller communities and rural regions. Local differences are more likely to involve delivery time, return-shipping transit and access to an appropriate professional for follow-up.
Major metropolitan areas
Begin remotely instead of traveling across the city to find a specialized genetic collection location.
Suburbs and smaller cities
At-home collection can make testing accessible when local specialty services are limited.
Rural and remote addresses
Allow for possible differences in kit delivery and sample-return transit when planning your timeline.
Local clinical follow-up
Questions about folate deficiency, anemia, symptoms or medication response require appropriate clinical care and testing.
Evidence and editorial transparency
SLC19A1 Information Grounded in Public Health Resources
This guide separates the established function of the reduced folate carrier from the more limited conclusions that can be drawn from a consumer genetic variant.
It does not claim that one SLC19A1 SNP causes folate deficiency, blocks methylation or identifies a supplement requirement.
Educational content reviewed against NCBI, NIH Office of Dietary Supplements and MedlinePlus Genetics resources in July 2026.
NCBI Gene: Human SLC19A1
Official gene description, reduced folate carrier function, aliases and chromosome location.
GeneReviews: SLC19A1 Folate Transport Deficiency
Clinical distinction between pathogenic variants and ordinary consumer-test polymorphisms.
NIH Office of Dietary Supplements: Folate
Folate function, one-carbon reactions, nutrient status and health-professional guidance.
MedlinePlus: Interpreting Genetic Results
Why genetic findings require medical, family and test-specific context.
This page and the related genetic test provide educational genetic and wellness information. They are not intended to diagnose, treat, cure or prevent disease. An SLC19A1 genotype does not measure current folate intake, intestinal absorption, intracellular folate, blood folate, red-blood-cell folate or transporter activity. Do not change medication, supplements, diet or medical care based only on a genetic report. Discuss important health decisions with a qualified healthcare professional.
Direct answers about SLC19A1
SLC19A1 Gene and Methylation FAQs
Clear answers about folate transport, SLC19A1 variants, RFC terminology and genetic methylation reports.
What does SLC19A1 stand for?
SLC19A1 stands for solute carrier family 19 member 1. It is the official gene symbol for the gene that encodes the reduced folate carrier.
What is the main function of SLC19A1?
SLC19A1 encodes a membrane transport protein that helps move reduced folates across cell membranes and regulate folate availability inside cells.
Is SLC19A1 a methylation enzyme?
No. It is a folate transporter. It is connected to methylation because intracellular folate supports one-carbon reactions involved in methionine metabolism, nucleotide synthesis and methyl-donor production.
Does an SLC19A1 variant mean I have folate deficiency?
No. A genetic variant does not measure your current folate status and cannot diagnose a deficiency. Current nutrient status requires appropriate clinical assessment and laboratory testing.
Does SLC19A1 control folate absorption from food?
SLC19A1 primarily supports folate transport across cell membranes. Intestinal folate absorption is mainly associated with another transporter encoded by SLC46A1. An SLC19A1 SNP does not prove that you cannot absorb food folate.
Is SLC19A1 the same as RFC1?
The SLC19A1 protein is commonly called the reduced folate carrier, or RFC. Some older sources use RFC1 as an alias, but RFC1 is also the official symbol of a different gene. Using SLC19A1 avoids this naming confusion.
Is a common SLC19A1 SNP the same as folate transport deficiency?
No. SLC19A1-related folate transport deficiency is a rare clinical condition associated with pathogenic variants affecting both gene copies. A common SNP in an educational methylation report does not diagnose that condition.
Why should SLC19A1 be reviewed with other genes?
SLC19A1 handles one transport step. Other genes influence folate conversion, vitamin B12-dependent reactions, homocysteine recycling and related methylation processes. A broader panel can provide better pathway context.
Can I order an SLC19A1 test from anywhere in the US?
SLC19A1 may be included within an at-home methylation gene panel available to US customers. Confirm the current panel coverage and visit the testing locations hub for state- and city-specific information.
What should I check before ordering?
Confirm that SLC19A1 is included, identify the exact variants reviewed, examine the other genes in the panel, check the report format and read the testing limitations. Start with the pre-order methylation test guide.
Make an informed testing decision
Review More Than One Folate-Related Gene
SLC19A1 provides useful transport context, but a responsible methylation report should also explain the other genes, variants and pathways included in the panel.
Educational genetic testing only. Not a diagnostic, folate-level, absorption or real-time transporter-activity test.