TFR2 Gene Test (Transferrin Receptor 2, Iron Overload Risk)

• Identify whether you carry rare TFR2 mutations that cause or contribute to hereditary haemochromatosis type 3, a form of genetic iron overload.
• Help explain persistently raised serum iron, high transferrin saturation, and liver iron loading that is not fully accounted for by HFE variants or lifestyle factors.
• Inform personalised iron monitoring, including how often to track ferritin and transferrin saturation and when to consider imaging or therapeutic phlebotomy discussions with a clinician.
• Provide context for how strongly you may be predisposed to iron accumulation in the liver, heart, pancreas, and endocrine organs across adulthood.
• Clarify your baseline iron-sensing profile alongside blood markers and clinical data, so long-term prevention and performance plans can be built around your biology.

TFR2 encodes transferrin receptor 2, a transmembrane glycoprotein expressed mainly in hepatocytes and erythroid cells. It is homologous to the classical transferrin receptor 1, but its primary role is in iron sensing and hepcidin regulation rather than general cellular iron uptake.

The hepatic form of TFR2 binds diferric transferrin in the bloodstream and helps the liver gauge circulating iron levels. This signalling contributes to hepcidin transcription, which in turn regulates iron absorption from the gut and iron release from macrophages. Loss-of-function mutations in TFR2 cause hereditary haemochromatosis type 3, an autosomal recessive iron overload disorder.

TFR2 sits at a key junction between circulating iron signals and hepcidin production in the liver. When diferric transferrin levels rise, TFR2 is stabilised at the hepatocyte surface and participates in signalling that increases hepcidin expression, which then reduces intestinal iron absorption and promotes iron sequestration to prevent overload.

In addition, TFR2 in erythroid cells appears to partner with the erythropoietin receptor and to modulate erythropoiesis in response to iron availability. Together, hepatic and erythroid TFR2 link systemic iron levels, hepcidin regulation, and red blood cell production. When TFR2 function is impaired, hepcidin is inappropriately low for the iron load, and iron absorption continues unchecked.

TFR2 contributes to three interconnected systems: regulation of body iron stores, protection of organs from iron-mediated damage, and coordination between iron availability and red blood cell production. Iron is essential for haemoglobin and mitochondrial function, but excess iron catalyses the formation of reactive oxygen species that damage tissues over time.

Hereditary haemochromatosis type 3 due to biallelic TFR2 mutations is characterised by progressive iron loading, particularly in the liver, leading to hepatomegaly, fibrosis, cirrhosis, and increased risk of hepatocellular carcinoma if not managed. Iron can also accumulate in heart, pancreas, and endocrine glands, contributing to cardiomyopathy, diabetes, and hormonal disturbances. Even outside classic haemochromatosis, common TFR2 variants have been associated with modest shifts in serum iron levels and iron status in population studies.

It is easy to assume that TFR2 testing and iron blood tests give the same information, but they answer different questions. TFR2 genotyping shows whether you carry rare mutations or common variants that alter the liver's iron-sensing machinery and predispose you to iron overload or altered iron handling. This genetic information is stable throughout life.

Ferritin, serum iron, and transferrin saturation show your current iron stores and circulating iron at a specific point in time under your present diet, lifestyle, and health status. They can be influenced by inflammation, alcohol intake, infection, and liver disease. In hereditary haemochromatosis, these markers often become abnormal long after the genetic predisposition is present, which is why combining genotype and phenotype gives a clearer picture of risk and timing.

The influence of TFR2 variants is shaped by diet, alcohol use, co-existing genes, and broader metabolic health, which means you have meaningful room to change the trajectory even if you carry risk variants. Several modifiable factors can either buffer or amplify genetic effects.

• Dietary iron and vitamin C intake: High intake of haem iron (for example large amounts of red meat) and vitamin C-rich drinks with meals can increase iron absorption and accelerate iron loading in people with TFR2-related haemochromatosis. Moderation and timing adjustments can slow iron accumulation.
• Alcohol and liver health: Alcohol stresses the liver and amplifies iron-related oxidative damage. In TFR2-related haemochromatosis or high iron states, limiting alcohol and supporting liver health is particularly important.
• Co-existing iron genes: Mutations in HFE or other iron genes can compound TFR2 effects. For example, combined HFE and TFR2 variants may lead to earlier or more pronounced iron loading than either alone.
• Inflammation and metabolic status: Chronic inflammation, obesity, and fatty liver can alter hepcidin and ferritin, sometimes masking underlying genetic iron loading or interacting with it to worsen liver outcomes.
• Blood donation and phlebotomy: Regular blood donation or medically supervised phlebotomy reduces iron stores and can protect organs in people with iron overload risk, often making a large difference even when TFR2 variants are present.
• Age, sex, and hormonal status: Men, postmenopausal women, and those without regular blood loss tend to manifest iron overload earlier if genetically predisposed. Menstruation and pregnancy can delay overt manifestations, but lifetime risk still exists.

Yes. Many individuals with TFR2 variants, especially common ones with modest effect sizes, have no noticeable symptoms and may only discover their genotype through DNA testing or family screening. Even carriers of a single pathogenic TFR2 mutation often remain asymptomatic but can pass the variant to children.

In hereditary haemochromatosis type 3, symptoms typically develop gradually and may be non-specific at first, such as fatigue, joint pain, or mild liver enzyme elevation. Without testing and early monitoring, significant iron loading can remain silent until fibrosis or organ dysfunction appears. This is why genetic and blood-based screening is valuable in at-risk individuals.

TFR2 genotypes mainly differ in how they affect receptor structure and function, the liver's iron-sensing capacity, and hepcidin regulation. Understanding your pattern helps tailor monitoring and lifestyle rather than treating iron overload as unpredictable.

• Normal or reference pattern: Individuals without known functional TFR2 variants have typical receptor function. Iron status still depends heavily on diet, blood loss, liver health, and other genes.
• Common regulatory and coding variants: Population variants can modestly adjust serum iron levels and transferrin saturation. Alone, they often have small effects but can contribute to lower or higher iron set points, especially when combined with TMPRSS6 or HFE variants.
• Biallelic pathogenic TFR2 mutations (hereditary haemochromatosis type 3): Two disease-causing variants, either identical or compound heterozygous, result in impaired hepcidin activation and progressive iron overload. These individuals are at risk for significant iron loading at a younger age than typical HFE homozygotes.
• Combined TFR2 and HFE or other iron gene genotypes: Mixed genotypes can refine risk and affect age of onset and severity of iron overload. Specialist interpretation is often needed in these cases.

For DNA-based TFR2 testing, preparation is straightforward because your genotype does not change with diet, iron levels, or illness. The key step is discussing with your clinician the reasons for testing, such as unexplained iron overload, family history, or early liver disease.

Cheek swab, saliva, or blood-based TFR2 genotyping does not require fasting. If TFR2 testing is combined with iron studies and liver markers, you may be asked to have a morning blood draw and to avoid iron supplements just before testing, so that results better reflect your usual baseline.

A TFR2 test is most useful when the result will change how you approach iron investigations, monitoring, or treatment. It becomes particularly informative when iron studies and clinical context raise suspicion of genetic iron overload beyond HFE variants alone.

• Elevated ferritin and transferrin saturation without clear cause: If you have unexplained iron overload, especially with normal or non-diagnostic HFE testing, TFR2 genotyping can help identify hereditary haemochromatosis type 3 or contributing variants.
• Early-onset iron overload or liver disease: Iron loading or liver problems at a younger age than usual, or in the absence of heavy alcohol use or viral hepatitis, can prompt TFR2 testing as part of a broader haemochromatosis workup.
• Family history of haemochromatosis or unexplained high iron: Relatives of individuals with iron overload may benefit from TFR2 and other iron gene testing to clarify their own risk and monitoring needs.
• Comprehensive iron and longevity planning: For individuals using a full preventive health approach, TFR2 sits alongside TMPRSS6, HFE, and iron studies to inform life-long strategies for avoiding both deficiency and overload.