Hereditary haemochromatosis

Hereditary haemochromatosis is an inherited condition in which the body absorbs iron without limit. It is common in people of European ancestry, and in men it brings more liver disease, joint replacements, liver cancer, dementia and earlier death, with excess harm even in men never diagnosed. The damage is largely preventable by regular blood removal, which makes it the clearest human evidence that chronic iron excess does lasting harm.

If your ferritin is high while inflammation markers are normal and your transferrin saturation is above about 45%, ask for a haemochromatosis work-up. If it is confirmed, it needs clinical management, usually regular blood removal to keep iron down.

What it is

People who inherit two faulty copies of the HFE gene lose the brake on iron absorption. That matters because the body has no regulated way to get rid of iron, so whatever is absorbed accumulates. About 1 in 150 people of European ancestry carry two copies.^[1]

What it does over a lifetime

The best numbers come from about 450,000 UK Biobank adults followed for over a decade. Men with two copies of the main HFE variant were estimated by age 80 to have died more often (about 33% against 25%), to have had more joint replacements (28% against 17%) and more liver disease (20% against 8%), and to have had excess dementia, delirium and Parkinson's disease. The excess held even in men never diagnosed with haemochromatosis.^[2] Their risk of liver cancer was roughly ten times higher.^[3]

Women with the same genotype had more liver disease, joint replacements and delirium, but less excess than men,^[4] and no clear excess in deaths.^[5]

Why it matters beyond the condition

Haemochromatosis is a natural experiment. Its harms are hard outcomes, they build up over decades, and they are largely preventable by keeping iron down, which is strong evidence that chronic iron excess itself causes cumulative damage. It anchors the wider case on Iron and aging that slowly rising iron in ordinary adults is worth watching.

Brain iron

Lowering body iron does not seem to clear brain iron. In a small study of people with haemochromatosis, blood ferritin and how often they had been bled poorly predicted how much iron sat in their deep brain regions.^[6]

How it is spotted

A high ferritin result is often the first clue. Ferritin also rises with inflammation, so a high value is read alongside an inflammation marker (high-sensitivity C-reactive protein) and transferrin saturation, the share of the blood's iron-carrying protein that is loaded with iron. High ferritin with normal inflammation and saturation above about 45% is the point at which a haemochromatosis work-up is appropriate.

What to do

Get ferritin and transferrin saturation measured as part of routine blood tests.
Ask for a work-up if both point to iron overload rather than inflammation.
Leave treatment to a clinician. Haemochromatosis changes the calculus on iron entirely and needs clinical management; don't self-treat with blood donation or diet alone.