A groundbreaking study has identified areas with the highest concentrations of a genetic condition dubbed the "Celtic Curse". Researchers have found that residents of the Outer Hebrides and north-west Ireland face the greatest likelihood of contracting haemochromatosis.

This disorder triggers a hazardous accumulation of iron within the body and, without intervention, can result in liver cancer, arthritis and other grave health complications. This marks the inaugural occasion that genetic susceptibility to haemochromatosis has been charted throughout the UK and Ireland, notwithstanding its notably high occurrence amongst Scottish and Irish populations. Specialists suggest that directing genetic testing for the disorder towards these high-priority regions could facilitate earlier identification of vulnerable individuals.

The investigation team noted that haemochromatosis manifestations can progress across several decades as elevated iron concentrations inflict harm upon vital organs. However, prompt diagnosis and intervention – including routine blood donation to diminish iron levels – proves crucial in averting liver damage, liver cancer and arthritis.

The disorder stems from minute alterations in DNA - termed genetic variants - which may be inherited through family lines. Researchers indicate that within the UK and Ireland, the principal risk element is a genetic variant designated C282Y.

Academics at the University of Edinburgh examined genetic information from over 400,000 participants in the UK BioBank and Viking Genes studies to establish the distribution of the C282Y variant across 29 territories of the British Isles and Ireland.

Research published in Nature Communications reveals that individuals with north-west Irish heritage face the greatest likelihood of developing haemochromatosis, with approximately one in 54 people carrying the genetic variant.

Following closely behind are residents of the Outer Hebrides (one in 62) and Northern Ireland (one in 71). Mainland Scotland – especially Glasgow and the south-west – also shows elevated risk, with roughly one in 117 people bearing the variant, lending credence to the condition's "Celtic Curse" moniker, according to researchers.

The study's authors suggest that concentrating genetic screening efforts in these high-risk areas would identify the greatest number of affected individuals.

Investigators also analysed haemochromatosis cases throughout NHS England, uncovering over 70,000 diagnoses.

White Irish individuals were nearly four times more likely to receive a diagnosis compared to white British people.

Within the white British population, Liverpudlians were 11 times more prone to diagnosis than Kent residents.

Researchers attribute this to historic Irish migration – during the 1850s, over 20% of Liverpool's inhabitants were Irish.

Whilst haemochromatosis prevalence in England generally mirrors genetic risk patterns, certain areas – Birmingham, Cumbria, Northumberland and Durham – show unexpectedly low diagnosis rates. Scientists suggest that regions in England where under-diagnosis may be prevalent could benefit from genetic screening to uncover additional cases.

Data on the prevalence of Haemochromatosis from the NHS is not available for Scotland, Wales and Northern Ireland, hence these areas could not be included in the study.

Professor Jim Flett Wilson, chair of human genetics at the University of Edinburgh, stated: "If untreated, the iron-overload disease haemochromatosis can lead to liver cancer, arthritis and other poor outcomes.

"We have demonstrated that the risk in the Hebrides and Northern Ireland is much higher than previously believed, 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, CEO of the charity Haemochromatosis UK which funded the study, commented: "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 haemochromatosis.

"As a charity we have already begun work on targeting and prioritising 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 the Western Isles, who has haemochromatosis, is backing the call for community screening for haemochromatosis genetic variants in the Western Isles.

He stated: "This research writes the case for community-wide screening in the Western Isles, Northern Ireland, and other haemochromatosis 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 offers a contained and distinct population sample to start from."

He further added: "Early identification, which I was fortunate 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."