Iron overload: a silent killer


"Haemochromatosis: Canada's most common genetic disorder," reads a prominent search-engine result.

But what, you may ask, is the relevance of this to you?

If you trawl through Cyberspace, you'll soon notice that the Canadian Haemochromatosis Society isn't alone in recognising haemochromatosis – or iron overload – as the most common genetic disorder. Worldwide, experts now realise that genetic haemochromatosis is far more common than previously thought. And they're concerned, because the health effects can be devastating.

Although genetic haemochromatosis has been recognised for more than a century, research into this field has accelerated during the past 20 years. At the forefront of research into the specific impact on South Africans is Dr Monique Zaahl from the Department of Genetics at the University of Stellenbosch.

During the past few years Dr Zaahl investigated the role of gene mutations involved in iron homeostasis, since it's known that a faulty iron-regulating system in the body is associated not only with genetic haemochromatosis, but also with serious illnesses such as throat cancer, multiple sclerosis (MS) and porphyria cutanea tarda*.

Results of her research have led to a better understanding of the mechanisms involved in iron metabolism and the above-mentioned diseases. And thanks to her, specific genetic tests for the Indian and African population groups have now been developed.

Haemochromatosis: early detection possible

Hereditary, or genetic, haemochromatosis is characterised by excessive absorption and storage of iron. Left untreated, it eventually leads to damage and impairment of many of the organs, including the liver, pancreas and endocrine glands.

For decades, it was believed that the disorder was mainly restricted to Caucasians and men. Now scientists know that it can affect people of all races and that women are at equal risk, even though menstruation protects most women throughout the reproductive years.

Currently, the most effective way of treating genetic haemochromatosis is by means of the ancient practice of bloodletting. For this reason, people with this disorder are encouraged to regularly donate blood, but scientists hope that other treatment methods may soon be available.

But even though the solution to the problem is simple, the condition often goes undetected for years – until serious, life-threatening disease occurs. Fortunately, it's now possible to test for three gene mutations that have been linked to genetic haemochromatosis. So, early detection is a reality.

Tests for other diseases

According to Dr Zaahl, more gene mutations have been found, linking iron-metabolism problems to a host of other diseases. As a result, genetic tests have been developed that now make early screening for these diseases possible.

One example is throat cancer – a disease that, without genetic testing, is very often diagnosed too late. Another example is ferroportin disease, in which an individual presents with anaemia despite having high levels of iron in the tissue.

Then there's multiple sclerosis (MS): it's possible that an overload of iron in the blood, which causes high levels of iron in the brain, might also play a role in the development of this chronic disease of the nervous system. Detecting iron-regulation problems through genetic testing may one day also help to prevent MS.

Cardiac arrhythmias and cardiomyopathy occur in 3-10% of people with genetic haemochromatosis, so screening for the associated mutations can also play a protective role here.

Iron overload is also associated with porphyria cutanea tarda, a hereditary liver condition in which light-exposed areas of the skin become blistered and fragile. It affects about 1 in 5000 people globally.

According to Dr Zaahl, future research will also investigate the role of iron overload in tuberculosis (TB), since a high iron level is known to play a key role in bacterial growth.

Better disease management as a result

"If you know a person is genetically predisposed to one of these conditions, you can keep an eye on him or her," explains Dr Zaahl. "There are very few genetic disorders that can be treated. But a problem with iron metabolism can easily be treated and managed so that it doesn’t cause serious harm."

Thanks to the latest developments, knowing whether a person is at risk of an iron disorder now merely involves taking a DNA sample and getting a simple lab test done. The test is relatively inexpensive (it costs no more than an average consultation with a specialist) and it doesn't take much time, according to Dr Zaahl.

Unfortunately, many South African doctors still don't know enough about haemochromatosis, or are unaware of the fact that iron overload is linked to several other diseases, says Dr Zaahl. Many doctors don't test for it, in which case the condition isn't properly treated.

What to do

If you have reason to suspect that you or a family member could have an iron-overload disorder, it might be a good idea to specifically ask your doctor to test for the relevant gene mutations. Alternatively, you can contact a genetic testing lab directly and ask them to do the testing for you.

Be aware of the symptoms of iron overload, but don't delay testing. These symptoms often only occur when organ damage is already underway:

  • Chronic fatigue
  • Arthritis
  • Cirrhosis and enlarged liver
  • Skin inflammation/blistering
  • Diabetes type 2
  • Impotence
  • Irregular menstruation or amenorrhoea (lack of menstruation)
  • Abdominal pain
  • Frequent diarrhoea
  • Mood swings and depression
  • Irregular heartbeat or arrhythmia

For more information on genetic testing, call GENEDiagnostics on 021 808 2980.

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