Summary

Your HFE C282Y result determines whether you carry the most common hereditary hemochromatosis variant — homozygotes (AA) absorb significantly more iron than they can use, leading to progressive organ damage if unmonitored, but the condition is completely manageable with early detection and simple intervention (blood donation).

Genotype spectrum

GG (Cys/Cys — normal)

Your iron absorption self-regulates. Ferritin levels track dietary intake and physiological need without accumulating excess.

GA (Cys/Tyr — carrier)

You absorb iron slightly more efficiently than GG carriers. In contexts where iron deficiency is common (athletes, vegetarians, menstruation), this is a genuine advantage — you're more resistant to iron deficiency.

AA (Tyr/Tyr — homozygous)

This is one of the most actionable findings in your entire genetic profile. HH is completely manageable.

Practical takeaway

For AA Carriers (C282Y Homozygous — Clinical Action Required)

Immediate:
• Get ferritin and transferrin saturation tested. This is not optional lifestyle advice — it's clinical genetics.
• Ferritin >300 ng/mL (men) or >200 ng/mL (women): GP referral for haematology assessment and phlebotomy plan.
• Transferrin saturation >45%: Consistent with iron overload phenotype. Confirm with repeat testing.

Iron reduction:
• Blood donation: In many countries, C282Y homozygotes can donate blood therapeutically. This removes iron AND helps others. Check with your blood service — some require GP authorisation noting HH.
• Therapeutic phlebotomy: If ferritin is significantly elevated, initial phase may require weekly or biweekly phlebotomy until ferritin reaches 50-100 ng/mL. Then maintenance 2-4x/year.

Dietary adjustments:
• Avoid iron supplements. Unless specifically prescribed for documented deficiency (rare in your genotype).
• Reduce vitamin C supplements with meals. Vitamin C enhances non-heme iron absorption. You don't need absorption enhancement.
• Moderate red meat intake. Heme iron (from meat) is absorbed at 15-35% regardless of iron status — your HFE mutation makes this worse. You don't need to eliminate meat, but don't eat steak daily.
• Tea and coffee with meals. Tannins and polyphenols inhibit iron absorption — for you, this is a dietary tool. (This is the opposite of advice for iron-deficient individuals.)
• Cast iron cookware. Adds dietary iron to food. Consider stainless steel or non-stick alternatives.
• Alcohol moderation. Alcohol accelerates iron-mediated liver damage synergistically. If ferritin is elevated, alcohol should be minimised until normalised. Even after normalisation, moderation matters.

Monitoring:
• Ferritin every 3-6 months during initial reduction phase.
• Every 6-12 months during maintenance.
• Liver function tests (ALT, AST) annually.
• If ferritin was >1000 ng/mL at discovery: liver biopsy or FibroScan may be warranted to assess fibrosis.

What "working" looks like:
• Ferritin maintained at 50-100 ng/mL
• Normal transferrin saturation (<45%)
• Normal liver function tests
• Resolution of fatigue and joint pain if present
• If treated be

Evidence detail

What This Gene Does

HFE produces the HFE protein, which regulates iron absorption in the gut by modulating the interaction between transferrin receptor and hepcidin — the master iron-regulating hormone. When HFE functions normally, iron absorption self-adjusts: low iron stores → more absorption, high iron stores → less absorption. The C282Y mutation (cysteine → tyrosine at position 282) disrupts HFE's ability to reach the cell surface, effectively removing the brake on iron absorption.

This isn't subtle. C282Y homozygotes (AA) absorb 2-3x more dietary iron than their body needs, and the excess accumulates in the liver, heart, pancreas, and joints over decades. Hereditary hemochromatosis (HH) is the most common genetic disorder in people of Northern European descent — and also the most treatable when caught early.

Mechanism

The iron regulation system works like this:

1. Dietary iron is absorbed in the duodenum, transported across enterocytes by DMT1 (import) and ferroportin (export to blood).
2. Hepcidin is the master regulator — produced by the liver when iron stores are sufficient, it degrades ferroportin, blocking iron export from gut cells → reduced absorption.
3. HFE protein is required for proper hepcidin signalling. Normal HFE detects high transferrin saturation (high iron) and signals the liver to produce more hepcidin.
4. C282Y mutation prevents HFE from reaching the cell surface (disrupts disulfide bond → misfolding → ER retention). Without functional HFE, hepcidin production fails to respond to iron levels. Hepcidin stays inappropriately low → ferroportin stays active → iron keeps being absorbed regardless of body iron stores.

Why this causes organ damage:

Excess iron accumulates in parenchymal cells (liver hepatocytes first, then pancreatic beta-cells, cardiac myocytes, joint synovium). Iron is a potent catalyst for Fenton chemistry: Fe²⁺ + H₂O₂ → Fe³⁺ + OH• + OH⁻. The hydroxyl radical (OH•) is the most reactive oxygen species in biology. Progressive oxidative damage → fibrosis → organ failure.

The timeline:

Iron accumulation is gradual — typically 0.5-1.0g per year in untreated C282Y homozygotes. Liver iron reaches pathological levels (>80 μmol/g dry weight) by age 40-60 in men. Women accumulate slower due to menstrual iron loss. Symptoms typically appear in the 4th-5th decade: fatigue, joint pain (especially 2nd/3rd metacarpophalangeal joints), abnormal liver function tests, skin bronzing, diabetes.

Why phlebotomy works:

Each unit of blood removed contains ~250mg of iron. Regular blood removal forces the body to mobilise stored iron for new red blood cell production, effectively depleting tissue iron stores. Target: ferritin 50-100 ng/mL. Once achieved, maintenance phlebotomy (2-4x/year) prevents re-accumulation.

HFE C282Y

Summary

Genotype spectrum

Practical takeaway

Evidence detail

Sources (10)