Researchers at the Mater Hospital, Dublin, have identified a strong association between a "Celtic gene" and a blood disorder called haemochromatosis.
Dr John Crowe of the hospital's centre for liver disease, told a conference at the weekend of his findings that 97 per cent of Irish patients with the disease have the unique genetic marker.
International delegates at the conference in the Royal College of Surgeons in Ireland heard the gene had been traced to a mutation which affected the Celtic race between 800 and 1000 AD.
High levels of the altered gene have been identified in the UK, the east coast of the United States and Australia. These countries have all seen high emigration from Ireland.
It has also been identified in Denmark and parts of southern Sweden, leading to speculation that the enforced migration of Irish slaves by the Vikings resulted in the importation of the gene to parts of Scandinavia.
Haemochromatosis is the result of over absorption of iron by the body. The excess iron is deposited in the liver, the pancreas, the heart and the pituitary gland, giving rise to the disease manifestations. These include a bronzed skin pigmentation, diabetes, liver enlargement, arthritis and heart failure. Symptoms are first noticed between the ages of 40 and 60 years.
Dr Crowe and his colleagues examined the DNA from 800 randomly selected newly-born babies and found the Celtic gene present in one out of 86 neonates. This represents the highest frequency for the gene in the world.
The researchers have asked whether we need to introduce a national screening programme for haemochromatosis. This could be achieved either by genetic screening at birth or by looking for excessive iron in early adulthood.
They have alerted doctors to screen for haemochromatosis in patients with chronic liver disease, diabetes, arthritis and heart disease. Treatment is inexpensive and prevents the progression of the disease. Therapy involves the twice weekly removal of 500 mls of the patient's blood for one to two years initially.
One in five Irish people are carriers of the gene but further research is recommended to discover how many will contract the disease.