Screening for hereditary haemochromatosis should be implemented nowBMJ 2000; 320 doi: https://doi.org/10.1136/bmj.320.7228.183 (Published 15 January 2000) Cite this as: BMJ 2000;320:183
- Katrina Allen (), paediatric gastroenterologist,
- Robert Williamson, director
EDITOR—The editorial by Haddow and Bradley on population screening for haemochromatosis concludes that now is too early to start population screening because of uncertainties about the proportion of homozygotes who will express symptoms of the disease.1 Haemochromatosis has been recognised as a clinical entity for over 150 years, but the gene that is mutated was not identified until 1996. Clinical haemochromatosis, defined by the presence of abnormal serum iron variables, has consistently been estimated to affect between 1 in 200 and 1 in 500 white people.2 3 The incidence of homozygotes for the more severe and common of the two mutations, C282Y, has been shown to be about 1 in 250 in all white populations studied. At least half of those with the major predisposing genotype (C282Y homozygosity) are likely to develop symptoms and signs of the disease.
A likely “favourable ratio” of one individual benefiting for every two in whom prophylactic phlebotomy is started on the basis of genotype tips the scales in favour of population based genetic screening. If gene testing is offered many individuals at high risk will be identified before symptoms develop and therefore will avoid serious but preventable illnesses.
We believe that genetic population screening is a correct strategy because haemochromatosis is common, preventable, and treatable. Screening before symptoms develop would result in it becoming rare.4 Testing can be undertaken in adults aged below 30, and prevention (regular blood donation) is not onerous. A simple and inexpensive mouthwash test is all that is required for DNA analysis for the affected gene. Unlike with other gene tests, there are few ethical issues to be balanced against the clinical benefits.
The public health issue revolves around the risk-benefit ratio, as is the case for screening for high cholesterol concentrations or hypertension. The link between the risk factor (C282Y homozygosity) and disease expression is tighter for haemochromatosis, and the medical management (regular blood donation) is far less onerous and costly than the lifelong daily drug treatment prescribed for hypertension or hypercholesterolaemia. We believe that to benefit all those at risk there is an ethical imperative to implement screening for the major mutation causing haemochromatosis now, rather than wait years for confirmation of what is currently known—that at least half of those with the predisposing genotype will develop some form of the disease.