New research maps genetic “hotspots” for hemochromatosis, revealing uneven risk and possible underdiagnosis across the UK and Ireland.
A new study indicates that residents of the Outer Hebrides and north-west Ireland face the greatest likelihood of developing a hereditary disorder that causes the body to accumulate excessive iron. This condition, hemochromatosis—also known as the ‘Celtic curse’ – can lead to serious health problems if left untreated.
Researchers say this is the first comprehensive effort to chart genetic susceptibility to hemochromatosis across the UK and Ireland, even though the illness has long been recognized as more common among people of Scottish and Irish descent. The findings suggest that directing genetic screening toward the highest risk regions could allow doctors to identify vulnerable individuals sooner and reduce the risk of long-term complications.
Hemochromatosis develops gradually. Over many years, excess iron can build up in vital organs, increasing the risk of liver damage, liver cancer, and arthritis. Detecting the disorder early is critical, as treatment is straightforward. Regular blood donation lowers iron levels and can prevent many of the most serious outcomes.
The disease results from inherited changes in DNA known as genetic variants. In the UK and Ireland, the strongest known risk factor is a variant called C282Y.
Mapping genetic risk across the British Isles
To better understand where this risk is concentrated, scientists at the University of Edinburgh examined genetic information from more than 400,000 participants in the UK BioBank and Viking Genes projects. They assessed how frequently the C282Y variant appears in 29 regions across the British Isles and Ireland.
The highest estimated carrier rate was found among people with ancestry from north-west Ireland, where about one in 54 individuals carry the variant. The next highest rates were observed in the Outer Hebrides (one in 62) and Northern Ireland (one in 71).
Map of the landscape of hereditary hemochromatosis risk across the UK and Ireland. Areas with a higher frequency of the disease-causing C282Y genetic variant are indicated in green. Hatching is used to represent two communities in Northern Ireland, each with different risks. Credit: University of EdinburghElevated risk was also identified in mainland Scotland, particularly in Glasgow and southwest Scotland, where roughly one in 117 people are estimated to carry the variant. These findings reinforce the historical association reflected in the nickname ‘Celtic Curse’.
According to the researchers, concentrating screening programs in these higher risk communities could uncover a substantial number of undiagnosed cases.
Diagnosis patterns and possible under-diagnosis
The team also reviewed NHS England records and identified more than 70,000 diagnosed cases of hemochromatosis. Diagnosis rates were nearly four times higher among white Irish individuals than among white British individuals.
Within the white British population, individuals from Liverpool were 11 times more likely to have a diagnosis than those from Kent. The researchers suggest that this difference may reflect historical migration patterns, as more than 20 percent of Liverpool’s population was Irish in the 1850s.
In general, the distribution of diagnosed cases in England mirrors the underlying genetic risk. However, several areas, including Birmingham, Cumbria, Northumberland, and Durham, show fewer diagnoses than expected based on their genetic profiles. Experts say these regions may have undetected cases and could benefit from expanded genetic screening.
Comparable NHS prevalence data were not available for Scotland, Wales, and Northern Ireland, so those nations were not included in the diagnosis analysis.
Expert reactions
Professor Jim Flett Wilson, Chair of Human Genetics at the University of Edinburgh, said: “If untreated, the iron-overload disease hemochromatosis can lead to liver cancer, arthritis, and other poor outcomes. We have shown that the risk in the Hebrides and Northern Ireland is much higher than previously thought, with about one in every 60 people at risk, about half of whom will develop the disease. Early detection prevents most of the adverse consequences and a simple treatment – giving blood – is available. The time has come to plan for community-wide genetic screening in these high-risk areas, to identify as many people as possible whose genes mean they are at high risk of this preventable illness.”
Jonathan Jelley MBE JP, CEO of Hemochromatosis UK, said: “Although there are other forms and genotypes that can lead to iron overload, available research indicates C282Y presents as the greatest risk. This hugely important work has the potential to lead to greater targeted awareness, increased diagnosis, and better treatment pathways for thousands of people affected by genetic hemochromatosis.
“As a charity, we have already begun work on targeting and prioritizing hotspot areas of the UK for support including with our National Helpline and clinician education. Using this study, we will continue to campaign for better allocation of public resources to this preventable condition that is all too often overlooked.”
Torcuil Crichton, the Labour MP for Na h-Eileanan an Iar (the Western Isles), has hemochromatosis and supports the call for community screening for hemochromatosis genetic variants in the Western Isles.
Torcuil Crichton MP said: “This research writes the case for community-wide screening in the Western Isles, Northern Ireland, and other hemochromatosis hotspots. I have previously raised this with Ministers in the House of Commons and this new evidence ought to be enough to persuade the UK National Screening Committee to review its position and approve a pilot screening programme. The Western Isles offer a contained and distinct population sample to start from.
“Early identification, which I was lucky to have, means a whole range of bad health outcomes can be avoided and I’ll be urging Ministers and the Screening Committee to reconsider their stance.”
Reference: “The landscape of hereditary haemochromatosis risk and diagnosis across the British Isles and Ireland” by Shona M. Kerr, Benjamin S. Fletcher, Gannie Tzoneva, Alan R. Shuldiner, Edmund Gilbert and James F. Wilson, 3 February 2026, Nature Communications.
DOI: 10.1038/s41467-025-65511-7
The study was funded by the charity Haemochromatosis-UK.
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date:2026-02-14 14:30:00