Genetic 'stealth' condition causes more cancers than thought

A common hereditary condition which causes the body to overload with iron, is linked to higher levels of disease and disability than previously thought, according to a cohort study using UK BioBank data.

Haemochromatosis had been thought to be a low-level health risk. The new findings, which suggest the opposite, could have immediate clinical implications since prevention of symptoms is possible with early screening and diagnosis.

'We've shown that hereditary haemochromatosis is actually a much more common and stealth disease,' said Professor David Melzer at the University of Exeter, who led the research. 'We now need to test ways of screening and diagnosing haemochromatosis earlier. It's exciting to think that better care might prevent so much unnecessary disease.'

Haemochromatosis occurs when a person has two mutated forms of a gene known as HEF, causing them to absorb too much iron from their diets. High levels of systemic iron can cause fatigue, joint disease, skin problems, sexual health issues – and if left untreated - organ damage.

Fortunately it can be treated; phlebotomy and other iron-reducing interventions improve clinical outcomes. Although one in 150 people of northern European descent have the double mutation, the number of people in the community with mutated HEF showing clinical symptoms had been considered low.

In this new study, 451,243 participants of European ancestry aged 40 to 70 years were followed up over seven years, with hospital records used to identify diagnosed conditions. The researchers discovered that having two mutated forms of HEF led to substantial morbidity in both men and women.

During the follow-up, 15.7 percent of men carrying the double mutation showed at least one occurrence of haemochromatosis-associated iron overload, liver disease, rheumatoid arthritis, osteoarthritis and diabetes mellitus versus 5.0 percent of men without mutations.

The respective estimates for women were 10.1 and 3.4 percent. Since haemochromatosis-associated iron overload is treatable, these findings justify re-examining options for expanded early screening and diagnosis.

Professor Melzer told CNN: 'We are now able to prevent so much unnecessary disease with a simple test and treatment, which is a win-win. It is safe, effective and cheap.'

He added: 'Economic data shows testing would pay for itself, because the cost of paying for treatment in late stages of disease is enormous.'

The BBC reports that the UK National Screening Committee said it will 'look at the evidence to screen for haemochromatosis in 2019/20, as part of its routine three yearly review.'

The study was published in the BMJ.