Genetic background of atopic dermatitis
Atopic dermatitis has a strong genetic background. In recent years, several genes have been identified that are associated with atopic eczema. They are responsible for the structure and function of the skin barrier, epidermal proliferation as well as differentiation, fat metabolism and immune response.
The disturbances in the epidermal barrier occur due to mutations (R501X and 2282del4) in the filaggrin-coding gene (FLG). Filaggrin is an essential structural protein of the uppermost layer of the skin. It helps in the construction (cell differentiation) of its cells. Lack of filaggrin causes scaly, dry skin and increases the risk of developing dermatitis threefold. FLG mutations are the strongest known risk factor for dermatitis. They are present in about 10 percent of the population in Europe.
A disturbed barrier function is then closely linked to a chronic immune activation in the skin as a consequence of a systemic allergic reaction. The immune system is disrupted ad doesn’t work as it should.
Genetics is therefore an important prerequisite for atopic eczema. If one of the parents is affected, their child is likely to suffer from eczema with a probability of about 30 %. If both parents are affected, the risk is 50 %. Usually, the disease occurs in the first year of life.
How lifestyle affects our health and genes
Although it may look like there’s nothing we can do about our genes, we certainly can. A relatively young scientific discipline called epigenetics deals with factors that affect gene expression. Many of us are born with a predisposition to a disease, but only some of us actually get sick. That is because in most cases, a stimulus is needed to de-/activate the gene. This can be diet, chemicals, heavy metals or even radioactivity. So although we can’t change our genome, we can influence which genes will get de-/activated. Unfortunately, this branch of science is still very young and doesn’t provide definitive answers and solutions for eczema. Nevertheless, it is important that we realize that we can regulate the expression (expression) of our genes through our way of life.
It is also interesting to know that some epigenetic changes in the genome (i.e. de-activation of a gene) may still (or only) affect the next 1-3 generations. We inherit not only a genetic structure, but also the de-/activation of various genes. This means that everything we eat, what we supply to our bodies, and all environmental factors get “inscribed” into our genome. Even if our lifestyle isn’t immediately reflected in our health, we pass (epi-)genetic information to our children.