AUSTRALIAN GASTROENTEROLOGY INSTITUTE
(educational
arm of the Gastroenterological Society of Australia) Website: www.gesa.org.au... Copies reviewed January 2006
HAEMOCHROMATOSIS
(Inherited Iron Overload Disease)
Introduction
Iron in small quantities is essential to life,
particularly for the function of haemoglobin, the blood protein which carries
oxygen to the tissues. Normally iron is taken into the body from food via the
intestine (known as "absorption"). Once the iron is absorbed the body
has no way of getting rid of excess iron. Some people have a disease called haemochromatosis
in which too much iron is absorbed. If this disease is not diagnosed and
treated, iron can damage vital organs and shorten a person's life.
What is Haemochromatosis?
Haemochromatosis is a genetic (family inherited)
disorder in which too much iron is taken into the body over and above the needs
of the body. It is caused by an abnormal gene, recently described and called the
HFE gene.
A gene is a code for a family likeness or characteristic. There are millions of
genes located on our 23 pairs of genetic material (called chromosomes) that we
inherit from our parents, half from each parent.
Individuals inheriting one haemochromatosis gene and one normal gene are called
carriers. Their iron absorption may be slightly higher than normal but most do
not absorb enough iron to cause any significant health problems. If two carriers
marry, each of their children has a 25% chance of inheriting two
haemochromatosis genes and a 50% chance of inheriting one haemochromatosis gene.
Carriers can now be identified by a new gene test for the HFE gene.
Individuals inheriting two haemochromatosis genes will absorb far too much iron.
This iron slowly builds up in the liver, heart, pancreas and other hormonal
glands and joints. It takes many years to build up iron to a level which causes
damage to these organs, but by the time the damage occurs, it is often too late
for the organ to repair itself and some permanent damage may remain.
How common is Haemochromatosis?
About one person in every 300 has the disease
haemochromatosis while about 12% of our Australian population are carriers of
one haemochromatosis gene. This means that in a city of the size of Sydney there
are approximately 12,000 people affected by the disease and 400,000 people
carrying one haemochromatosis gene. This makes haemochromatosis one of the
commonest genetic diseases in our society, although many people are only mildly
affected.
What are the symptoms Haemochromatosis?
Symptoms vary considerably among patients. The
symptoms resemble those of many other medical conditions, making diagnosis
difficult. The symptoms may include fatigue, weakness, weight loss, abdominal
discomfort and joint pain. A tanned appearance, not due to sun exposure, may
also occur. Other symptoms may develop later as a result of organ damage to the
liver, heart (palpitations, shortness of breath, chest pain), pancreas (thirst
or frequent urination as a result of diabetes), or other hormonal deficiencies
(loss of sex drive or body hair). However, most young people with the disease
have no symptoms or only minor symptoms in the early stages of the disease.
Who may be at risk of Haemochromatosis?
Blood relatives of patients (particularly close
relatives such as brothers, sisters and children).
Individuals with symptoms of the disease.
Individuals with diabetes, arthritis and certain
heart problems.
If you have some of the symptoms mentioned above, do
not overreact and conclude that you have haemochromatosis because there are many
other causes for such symptoms. See your family doctor and discuss your
concerns.
How is the diagnosis made?
A blood relative of someone with haemochromatosis should have a simple blood
test for the HFE gene to see if they are at high risk of haemochromatosis. This
blood test is available (after discussion with your general practitioner)
through usual pathology laboratories. In people without any family history of
haemochromatosis, the two most useful initial blood tests are:
Serum transferrin saturation (best test).
Serum ferritin (may be normal early in the
disease).
These tests can be done on the one sample of blood.
If the tests are abnormal on at least two occasions, a further blood test
looking for the HFE gene may be all that is required to confirm the diagnosis of
haemochromatosis. Some patients will require a liver biopsy to confirm the
diagnosis and/or assess the degree of damage to the liver. Liver biopsy involves
removal of a small piece of liver with a needle under local anaesthetic. It is a
safe procedure when done by a medical practitioner experienced in the technique.
Screening of relatives After a diagnosis of haemochromatosis is made, all
close relatives over the age of 10 years should be screened for haemochromatosis.
Close relatives include brothers, sisters, parents and children. Cousins, aunts
and uncles should also be tested, although the risk is much lower. Family
screening will include an examination by a doctor, with blood testing as
described above, to determine which family members are likely to have the
disease. In some cases, blood tests will need to be repeated in 2 years as
sometimes the excess iron does not become apparent until later life. Early
diagnosis and treatment of family members with the disease is essential to
prevent organ damage.
Is there are treatment? Yes, By removing about 500ml of blood, as in blood
donation, usually once a week, the body is stimulated to make more blood and
this uses up the excess iron. This is called "venesection
treatment". Depending on the amount of iron in the body, the initial
treatment may take one or two years. Blood tests are done to monitor the iron
removal. Once the excess iron has been removed, venesections are done about four
times a year to prevent iron building up again.
Treatment should continue for the rest of the
person's life.
Venesection treatment must only be done by medical or nursing staff experienced
in this technique. Venesections can be done at some hospitals, some pathology
laboratories or some general practices. On occasions, venesections can be
organised through blood banks, after referral from a specialist. Immediately
prior to a venesection, rest for 15 minutes and drink 500ml of fluid. After the
venesection, stand up slowly and sit in a chair for 15 minutes, keeping pressure
on your arm for 5 minutes where the needle was inserted.
How effective is the treatment? What is the outcome? There is good evidence that with removal of excess
iron, patients feel better, stronger, their tan colour lessens, liver size
decreases, diabetes may improve and heart function improves. If treatment has
been commenced early, damage to the liver and other organs may be completely
prevented. If cirrhosis (liver scarring) is present it is usually not reversed
by treatment, but should not get worse. Without venesection treatment, iron
continues to build up and organ damage continues. It is not possible to treat
haemochromatosis with a low iron diet, since iron is present in most foods, and
it is the iron already in the body which will cause damage. However, it is
advised that patients with haemochromatosis do not take iron tablets of any
type, nor vitamin tablets containing iron or vitamin C (ascorbic acid) as
vitamin C can increase iron absorption. People with haemochromatosis may also
consider reducing red meat intake (eg. to approximately 90-120 g/day). Alcoholic
drinks in small quantities (eg. two glasses or less per day) are not usually
harmful, but if there is liver damage your doctor may advise you to have no
alcohol.
Are there support groups? Yes. Some large hospitals have support groups for
patients and relatives with liver diseases and haemochromatosis. If not, you
could contact the :
Haemochromatosis Society of Australia,
412 Musgrave Road,
Coopers Plains,
QLD, 4108
Tel: (07) 3345 7583)
or the Australian Gastroenterology Institute:
145 Macquarie Street,
Sydney,
NSW, 2000
This brochure is provided as a public service and was prepared by an expert
committee of the Australian Gastroenterology Institute and endorsed by the
Australian Liver Association.
AUSTRALIAN GASTROENTEROLOGY INSTITUTE 