It's thought just one person was responsible for the genetic condition that is Haemochromatosis. The gene mutated roughly 2,000 years ago, in a time when our ancestor's diet was lacking in iron. Because life spans weren't as long as they are now, people probably didn't live long enough for the condition to trouble them. In fact, knowing their dietary limitations, having extra iron was probably a blessing. So nothing was done by nature to combat the mutation and it spread and prospered. It wasn't until relatively modern times when diets improved and people began to live longer, that the condition became a curse. Once considered a rare condition, Haemochromatosis is now acknowledged as one of the commonest inherited disorders, affecting one in two hundred people of western Caucasian descent. The hereditary form of the disease is most common among those of northern European ancestry, in particular those of British or Irish descent. It is the most common hereditary disease in Sweden and is caused by two mutations of a gene. Hereditary Haemochromatosis is mainly caused by a defect in a gene called HFE, which helps regulate the amount of iron absorbed from food. Iron is an essential nutrient found in many foods. The greatest amount is found in red meat and iron-fortified breads and cereals. In the body, iron becomes part of hemoglobin, a molecule in the blood that transports oxygen from the lungs to all body tissues. Healthy people usually absorb about 10 percent of the iron contained in the food they eat, which meets normal dietary requirements. People with Haemochromatosis absorb up to 30 percent of iron. Over time, they absorb and retain between five to 20 times more iron than the body needs. Because the body has no natural way to rid itself of the excess iron, it is stored in body tissues, specifically the liver, heart, and pancreas. The two known mutations of HFE are C282Y and H63D. C282Y is the most important. In people who inherit C282Y from both parents, the body absorbs too much iron and Haemochromatosis can result. Those who inherit the defective gene from only one parent are carriers for the disease but usually do not develop it; however, they still may have higher than average iron absorption. People who inherit a mutation from each parent are double carriers (homozygous or compound heterozygous). These individuals have a higher absorption of iron from their diet. With years, the increased amount of iron that is stored in the body may result in severe organ damage. Without treatment (regular bleeding), the disease can cause the liver, heart and pancreas to fail. Caught early, the condition causes no problems and life goes on as usual.
For diagrams and a very good explanation of this condition, see the New Zealand
Likewise, the Iron Disorders Institute article is also very good
The genetic ramifications of Consanguinity In our family trees, many of us have cousins marrying cousins. Consanguinity is the term applied where the parents of a child share a common ancestor |
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Haemochromatosis: "The Celtic Curse" |