Hereditary Haemochromatosis (HH)

What is Hereditary Haemochromatosis?
Statistics on Hereditary Haemochromatosis
Risk Factors for Hereditary Haemochromatosis
Progression of Hereditary Haemochromatosis
How is Hereditary Haemochromatosis Diagnosed?
Prognosis of Hereditary Haemochromatosis
How is Hereditary Haemochromatosis Treated?
Hereditary Haemochromatosis References

What is Hereditary Haemochromatosis?

Hereditary Haemochromatosis is an inherited disorder of iron metabolism where there is increased intestinal iron absorption leading to deposition and subsequent damage in multiple organs (joints, liver, heart, pancreas and pituitary).HH is an autosomal recessive condition - hence a person needs both copies (one from each parent) of the affectred gene to be abnormal to develop the disease.

Statistics on Hereditary Haemochromatosis

Hereditary Haemochromatosis is a common disease. Approximately 1 in 10 individuals carry one abnormal copy of the affected gene (carriers, heterozygotes) and about 1 in 400 have both copies of the abnormal gene.Middle aged males are more frequently and severely affected than women. The disease tends to present approximately ten years later in women (menstrual blood loss is protective).

Risk Factors for Hereditary Haemochromatosis

As mentioned above, having two copies of the abnormal (HFE) gene is the most important causative factor. Other factors such as excess alcohol consumption or dietary iron excess may also play a part.Haemochromatosis may also occur as a secondary event - that is not as a result of the genetic factors. It may occur with some serious anaemias (e.g. thalassaemia major) with repeated blood transfusions, due to dietery iron excess (rarely in western society) and also with chronic liver disease.

Progression of Hereditary Haemochromatosis

The course of the disease depends on a number of factors including sex, dietary iron intake, presence of associated liver toxins (especially alcohol) and genetics.With progressive iron accumulation and fibrosis, the following complications may be seen:

Liver cirrhosis: also liver failure, and high risk of developing liver cancer;

Diabetes mellitus - due to pancreatic damage;

Cardiomyopathy and arrhythmias (abnormal heart rhythms)- due to heart damage;

Impotence in men - due to testicular and/or pituitary damage.

How is Hereditary Haemochromatosis Diagnosed?

Liver function tests - often abnormal

Blood glucose: may be elevated suggesting diabetes;

Joint xrays - classically show chondrocalcinosis

ECG and echocardiography - if cardiomyopathy is suspected.

Prognosis of Hereditary Haemochromatosis

The prognosis largely depends on whether the disease is diagnosed early and treatment started accordingly - when there is normal life expectancy. If the disease is diagnosed later, after the onset of liver cirrhosis, diabetes, and heart abnormalities - then these are irreversible and life expectancy is shortened. Gonadal failure is also irreversive, hence impotence will not reverse with treatment of the disease.

How is Hereditary Haemochromatosis Treated?

Treatment for the disease is venesection (the taking of blood). This should be performed initially one to two times weekly until there is a moderate iron deficiency. Because iron will continue to accumulate venesection is needed every 2-3 months (1 unit) for the rest of the individual's life.Screening:1st degree relatives should be tested for an overload of iron and for the abnormal gene.

Hereditary Haemochromatosis References

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Hurst JW (Editor-in-chief). Medicine for the practicing physician. 4th edition Appleton and Lange 1996.
Kumar P, Clark M. CLINICAL MEDICINE. WB Saunders 2002
Longmore M, Wilkinson I, Torok E. OXFORD HANDBOOK OF CLINICAL MEDICINE. Oxford Universtiy Press. 2001
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