Surveys show a particular distribution pattern with large clusters and frequencies of gene mutations along the western European coastline. This led the development of the "Viking Hypothesis". Cluster locations and mapped patterns of this mutation correlate closely to the locations of Viking settlements in Europe established c.700 AD to c.1100 AD. The Vikings originally came from Norway, Sweden and Denmark. Viking ships made their way along the coastline of Europe in search of trade, riches, and land. Genetic studies suggest that the extremely high frequency patterns in some European countries are the result of migrations of Vikings and later Normans, indicating a genetic link between hereditary haemochromatosis and Viking ancestry. Modern times
In 1865, Armand Trousseau (a French internist) was one of the first to describe many of the symptoms of a diabetic patient with cirrhosis of the liver and bronzed skin color. The term haemochromatosis was first used by German pathologist Friedrich Daniel von Recklinghausen in 1889 when he described an accumulation of iron in body tissues. Identification of genetic factors
Although it was known most of the 20th century that most cases of haemochromatosis were inherited, they were incorrectly assumed to depend on a single gene.In 1935 J.H. Sheldon, a British physician, described the link to iron metabolism for the first time as well as demonstrating its hereditary nature.In 1996 Felder and colleagues identified the haemochromatosis gene, HFE gene. Felder found that the HFE gene has two main mutations, C282Y and H63D, which were the main cause of hereditary haemochromatosis.
Over many generations, the human body became well-adapted to a high level of iron content in the diet. Neolithic
In the Neolithic era, significant changes are thought to have occurred in both the environment and diet. Some communities of foragers migrated north, leading to changes in lifestyle and environment, with a decrease in temperatures and a change in the landscape which the foragers then needed to adapt to. As people began to develop and advance their tools, they learned new ways of producing food, and farming also slowly developed. These changes would have led to serious stress on the body and a decrease in the consumption of iron-rich foods. This transition is a key factor in the mutation of genes, especially those that regulated dietary iron absorption. Iron, which makes up 70% of red blood cell composition, is a critical micronutrient for effective thermoregulation in the body. Iron deficiency will lead to a drop in the core temperature. In the chilly and damp environments of Northern Europe, supplementary iron from food was necessary to keep temperatures regulated, however, without sufficient iron intake the human body would have started to store iron at higher rates than normal. In theory, the pressures caused by migrating north would have selected for a gene mutation that promoted greater absorption and storage of iron. Viking hypothesis
Studies and surveys conducted to determine the frequencies of haemochromatosis help explain how the mutation migrated around the globe. In theory, the disease initially evolved from travelers migrating from the north.