Haemochromatosis is a condition characterized by the excessive absorption and storage of iron from an individual’s diet. Over time, this accumulation of iron can impact the function of various organs. The condition is often genetic in origin and develops gradually over many years.
Causes and Types of Haemochromatosis
The most common cause of haemochromatosis is an inherited genetic trait, known as primary or hereditary haemochromatosis. This type is linked to mutations in the HFE gene, which regulates the amount of iron the body absorbs from food. When this gene is faulty, the regulatory mechanism is compromised, leading to a gradual buildup of excess iron. For the condition to manifest, an individual must inherit a copy of this faulty gene from both parents.
Not everyone who inherits the genes will develop the condition, and the reasons for this are not fully understood. Rarer forms of hereditary haemochromatosis are caused by mutations in other genes involved in iron metabolism, such as HJV, HAMP, or TFR2. These can sometimes lead to juvenile haemochromatosis, a version that appears during childhood or adolescence.
A different form, known as secondary haemochromatosis, is not inherited but results from other medical conditions or treatments. Certain types of anemia that require frequent blood transfusions can lead to iron overload because transfused red blood cells are a significant source of iron. Other causes can include long-term kidney dialysis or chronic liver diseases, such as hepatitis C.
Signs and Symptoms of Iron Overload
The initial signs of haemochromatosis are often subtle and can be mistaken for other conditions. Persistent fatigue, general weakness, and unexplained weight loss are common early symptoms. Many people also experience joint pain, particularly in the knuckles and knees, and abdominal pain.
As iron levels continue to rise, more specific and serious symptoms can emerge as organs are affected. The liver is particularly vulnerable to iron overload, which can lead to an enlarged liver, scarring (cirrhosis), and an increased risk of liver cancer. When iron accumulates in the pancreas, it can disrupt insulin production, leading to diabetes.
The heart can also be damaged by excess iron, which may cause an irregular heartbeat (arrhythmia) or heart failure. A distinct sign of advanced haemochromatosis is a change in skin color, which may take on a bronze or gray hue due to iron deposits in the skin cells. In men, iron overload can lead to erectile dysfunction, while women may experience irregular periods or early menopause.
The Diagnostic Journey
The diagnostic process often begins when routine blood tests for other conditions reveal abnormalities in iron levels. The primary screening tools are blood tests that measure serum ferritin and transferrin saturation. Serum ferritin indicates the amount of iron stored in the body, while transferrin saturation measures the amount of iron being transported in the blood.
High levels of both ferritin and transferrin saturation suggest the possibility of iron overload and prompt further investigation. To confirm a diagnosis of hereditary haemochromatosis, genetic testing is performed. This test identifies specific mutations in the HFE gene, which are responsible for the majority of inherited cases. A physical examination may also reveal signs like skin discoloration or an enlarged liver.
In the past, a liver biopsy was a common procedure to assess the degree of iron accumulation and liver damage. This invasive test involves taking a small sample of liver tissue for analysis. However, with the accuracy of modern blood and genetic tests, liver biopsies are now used less frequently for initial diagnosis.
Managing Haemochromatosis
The standard treatment for haemochromatosis is a procedure called phlebotomy, which involves the regular removal of blood. This process is similar to donating blood and is highly effective at reducing the body’s iron levels. The goal of phlebotomy is to bring iron stores down to a normal range and prevent further organ damage. The frequency of these sessions varies depending on the severity of the iron overload at the time of diagnosis.
Initially, a patient may require phlebotomy once or twice a week. During this intensive phase, about a pint of blood is removed at each session to quickly lower iron levels. Once iron levels are stabilized, the patient transitions to a lifelong maintenance phase, where blood is removed less frequently, typically every few months, to keep iron stores in check.
Dietary adjustments are a supportive measure in managing haemochromatosis. Patients are often advised to avoid taking iron supplements or multivitamins that contain iron. It is also recommended to limit the intake of vitamin C supplements, as vitamin C can increase the absorption of iron from food. Limiting alcohol consumption is also advised because alcohol can increase the risk of liver damage.