Saturday, 24 March 2012

Type 1 Haemochromatosis

Type 1 Haemochromatosis Blog- Tom Howard (42888646)

Type 1 Haemochromatosis is a hereditary disease, meaning that it is passed down through families. It involves an over-intake of iron from the diet. The body is only able to expel certain amounts of iron per day and as a result, someone with haemochromatosis stores iron in organs and tissues such as the liver, skin and the heart.

Hereditary haemochromatosis is the most common single-gene disease in Western populations, affecting 1 out of every 200-300 people. It has approximately the same incidence in the population of Western countries as Type 1 diabetes.

It is caused by a defect of the HFE gene. The HFE gene is located on chromosome six, which is an autosome. (Genetics Home reference, 2006). Thus meaning that type 1 haemochromatosis affects both sexes equally, as chromosome 6 is not a sex chromosome. (Medic8, 2010).

Figure 1: HFE gene

Until recently it was unknown how the defect of the HFE gene caused the body to absorb copious amounts of iron from the diet in the intestines. Then in 2010, it was discovered that the HFE gene controls the levels of hepcidin in the bloodstream. Hepcidin is a hormone which is secreted by the liver; greater amounts of hepcidin correlate to lower amounts of iron in the blood. (Antonello P., 2010)

Figure 2: Hepcidin levels in people with and without haemochromatosis

Thus, a person who has a defect of the HFE gene (seen in figure 2b) will not produce enough hepcidin and as such, greater amounts of iron are released from the marcophages and absorbed by the lumen that line the intestines. The large amount of iron in the blood stream is eventually stored in organs such as the liver.

An overload of iron in organs can lead to serious health issues such as cirrhosis of the liver (scarring), an increased risk of liver cancer, heart arrhythmia and heart failure. Iron overload in the pancreas can cause a decrease in the production of insulin and thus can lead to diabetes. (Antonello P., 2010)

Thus with the knowledge gained from the recent discoveries, the levels of hepcidin can now be targeted by modern medicine to find a more suitable cure than the current taking of blood to remove iron.


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