Having a specific gene associated with psoriasis or a family history of the condition does not mean that a person will develop it. Genetic changes can make it more likely, but environmental triggers also seem to play a role.
The American Academy of Dermatology explains that if a parent, grandparent, or sibling has psoriasis, an individual has a higher chance of developing it.
People with psoriasis may also have mutations, or changes, in specific genes, suggesting a genetic involvement in its development. However, without a specific environmental trigger, psoriasis may never develop — even in someone with psoriasis-related genetic features.
As researchers learn more about how genetic factors can impact psoriasis, people who have relatives with the condition can start to develop a better understanding of how likely it is to affect them.
The reason that some people with the genetic features do not develop psoriasis is that:
- they may not have the right collection of genetic features
- they may not have had exposure to specific environmental triggers
This suggests that both environmental triggers and genes play a role in whether a person will develop psoriasis.
In other words, a person whose family members have psoriasis may have a higher chance of developing the condition themselves, but perhaps only if certain other factors are also present.
For this reason, it is not possible to predict who will develop psoriasis, and a person whose close relatives have psoriasis will not necessarily have it themselves.
Psoriasis is a systemic condition that affects various body systems and involves a malfunction in the immune system.
The immune system exists to resolve problems that arise when harmful substances, such as infections like a virus, invade the body. Inflammation plays a role in this reaction. Sometimes, however, the immune system malfunctions and reacts to a threat that does not exist.
This reaction and the resulting inflammation can lead to damage in various parts of the body. In the case of psoriasis, it triggers an overgrowth of skin cells and other symptoms.
Skin changes are the hallmark sign of psoriasis, but inflammation can occur elsewhere in the body. If it happens in the joints, it can lead to psoriatic arthritis.
What are the triggers for psoriasis?
In most cases, genetic changes are not enough to activate psoriasis. An environmental factor will also need to be present to trigger the condition.
Possible triggers include:
- chronic infections such as strep throat
- low humidity
- using some medications, including beta-blockers and lithium
Learn more here about the triggers of psoriasis.
Researchers have been investigating which genetic factors might make psoriasis more likely in some people. Different genetic changes may make specific types of psoriasis more likely.
Psoriasis-related genes mainly play a role in the immune system, and researchers have identified more than 80.
We detail some of them in the sections below:
A gene called HLA-Cw6 is one of the genes most associated with psoriasis. It has been found to be primarily associated with guttate psoriasis and type I early-onset psoriasis.
The gene tends to be common among people who are white compared to other races or ethnicities. People who carry the gene are more likely to experience stress, obesity, and strep throat.
People who have this gene and develop psoriasis tend to experience more symptoms on the trunk of their body, as well as on their legs and arms. They are also more likely to experience the Koebner phenomenon.
Changes in this gene can result in additional inflammation and could lead to psoriasis when specific environmental triggers are also present.
CARD14 appears to play a role in pustular psoriasis.
Changes in other genes and gene groups may impact how the immune system works by increasing the inflammatory response.
Many genes may play a role in psoriasis or increase a person’s susceptibility to the condition.
For example, the
Changes in the human leukocyte antigen (HLA) complex may increase the risk of psoriatic arthritis. This gene group plays a role in distinguishing between foreign invaders and body tissue.
Each type of psoriasis may involve changes in a number of genes. In addition, some genetic changes may be present across various types of psoriasis. One gene can also have a range of variants.
Researchers are continuing to look into various genes and their connections with psoriasis.
The process of determining which genes affect psoriasis is a difficult task involving the following steps:
- Researchers identify a genetic feature that is more common in people with psoriasis.
- They investigate how the gene functions in normal use.
- They look at how the gene behaves in a person with psoriasis, and how this behavior differs from its normal function.
How knowledge of genes can help
- Genetic factors increase a person’s susceptibility to psoriasis.
- Some specific genes may play a role in psoriatic changes.
If scientists can find out exactly which genes cause a condition and how to change them, they may be able to develop novel treatments and even a cure.
Biologic therapy is now a common treatment option for certain types of psoriasis. These drugs target specific components of the immune system. They are effective at reducing the number of flares and the severity of symptoms.
Researchers tend to agree that the most likely cause of psoriasis is that changes in specific immune-related genes combine with environmental triggers at a certain point in time.
Chance may play a minor role since a person probably needs a very specific combination of genetic changes for psoriasis to develop. Even then, psoriasis may not occur without a trigger, such as an infection.
Some triggers are avoidable, but others are not. For example, people get vaccinations and practice good hygiene to reduce the risk of infections, but it is not possible to prevent all illnesses.
If these factors are not in place, scientists believe that a person may not develop psoriasis in their lifetime.
At what age does psoriasis start?
What are the odds of inheriting psoriasis?
There is evidence to suggest that psoriasis can run in families and that genetic factors play a role. However, having a family member with psoriasis does not mean that a person will develop it themselves.
As researchers continue to learn more about the role of genes in psoriasis, new ways of treating and preventing the condition are emerging.
One day, this information might lead to a cure.