Hereditary Haemochromatosis (HH)

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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.

Who gets 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).

Predisposing Factors

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

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.

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