Haemochromatosis

Introduction

Haemochromatosis is a condition in which the amount of total body iron is increased. The excess iron is deposited in and causes damage to several organs, including the liver. Hereditary haemochromatosis is the commonest cause of haemochromatosis and has autosomal recessive inheritance.

Epidemiology

Hereditary haemochromatosis is the most common heritable genetic condition in Northern Europe. Most male patients are diagnosed at the age 40-50; females are usually diagnosed decades later due to menstrual iron loss.

Causes

Most cases of haemochromatosis are hereditary in nature.

Primary

Hereditary haemochromatosis (HHC)

Congenital acaeruloplasminaemia

Congenital atransferrinaemia

Secondary (from iron overload)

Parenteral iron-loading e.g. repeated transfusions

Iron-loading anaemia e.g. thalassaemia, sideroblastic anaemia

Liver disease

Pathophysiology

90% of patients with HHC have a homozygous C282Y mutation in HFE protein. This leads to increased absorption of dietary iron. Iron is deposited throughout the body and total iron may reach 60-80 grams (compared to 4 grams in healthy individuals).

The organs most affected are:

1. Liver
2. Pancreatic islets
3. Endocrine glands
4. Heart

Iron metabolism in HHC

The pathological mechanism is unclear. It is thought that the defective HFE cannot interact with transferrin, leading to reduced uptake of transferrin-associated iron. Consequently, enterocyte iron transporters are upregulated to increase intestinal iron absorption.

Liver damage

In the liver, iron deposition first starts in periportal hepatocytes and later extends to all hepatocytes. Fibrous septa gradually develop, leading to irregular nodules. Subsequent regeneration produces cirrhosis.

Clinical features

Most patients are asymptomatic. Symptomatic patients are usually males above the age 40.

The classic symptoms of haemochromatosis are:

1. Cirrhosis
2. Bronzed skin (leaden-grey skin pigmentation due to increased melanin)
3. Diabetes mellitus

Other features include:

• Fatigue and malaise
• Heart failure
• Arthritis with chondrocalcinosis due to calcium pyrophosphate deposition
• Sexual symptoms – impotence, loss of libido, testicular atrophy

Investigations

The most routinely used tests for haemochromatosis are bloods and genetic testing.

Management

The management options for haemochromatosis include venesection, organ treatment and dietary adjustments.

Venesection

Initial treatment involves weekly venesection of 500 mL blood (containing 250 mg iron) until serum iron is normal and ferritin levels <50 µg/L. This may take two years or more to achieve. Once iron and ferritin levels are well-controlled, venesection can be offered as required maintain normal ferritin levels.

Venesection can resolve liver and cardiac problems but will not resolve diabetes mellitus.

Organ treatment

Treat cirrhosis, diabetes and heart failure symptomatically.

Diet

The intake of alcohol, vitamin C and red meat should be limited. Substances that inhibit calcium absorption should be encouraged, such as high tannin tea.

Genetic screening

Family members of patient with HHC should be offered screening for the condition.

Prognosis

Pre-cirrhotic HHC has a normal life expectancy. Compared to other causes of cirrhosis, cirrhotic HHC has a good prognosis.

Hepatocellular carcinoma is an important cause of death in HHC.