Psoriasis begins in your immune system with a type of white blood cell called a T cell. These cells play a role in shielding your body against infections and diseases.
If you have psoriasis, however, these cells tend to go haywire, are mistakenly driven into action and attack healthy skin cells. When these T cells exhibit so much activity, they trigger other immune responses, resulting in swelling and quick skin cell turnover.1,2
Although researchers have pointed out some events that can influence the onset of psoriasis, the exact cause of this condition is yet to be determined.3 However, there are two known factors that are currently being studied that may predispose you or someone you know to psoriasis: environmental triggers and genetics.
Some Environmental Triggers Can Cause Psoriasis
Aside from rampant T cell activity that could influence your immune system, there are environmental triggers or risk factors that could cause psoriasis. These include:4,5,6
Having a Family History of Psoriasis Can Increase Your Chances Too
Another factor that can play a role in being diagnosed with psoriasis is having a family history of the disease. It is said that at least 1 in 3 people become affected with psoriasis if they have a close relative with this condition.7
Meanwhile, a child’s risk for psoriasis increases depending on how many parents are affected with the condition — the risk stands at 10 percent if one parent has psoriasis, but it goes up to 50 percent if both parents have the disease.8
Gene Mutations May Also Be Linked to Psoriasis
Since a family history of psoriasis could be a factor in having this condition, studies have been conducted to determine the exact genes that cause psoriasis. As highlighted by the National Psoriasis Foundation (NPF), around 25 genetic variants have already been discovered that can potentially raise a person’s risk for psoriatic disease.9
In 2012, researchers led by the Washington University School of Medicine in St. Louis, Missouri discovered the first gene that’s directly linked to psoriasis: CARD14. Mutated versions of this gene may result in plaque psoriasis, a common type of the condition, when the gene is activated by an environmental trigger. This study was co-authored by genetics professor Anne Bowcock, Ph.D. and Dr. Alan Menter of the Psoriasis Research Institute at the Baylor University Medical Center in Dallas, Texas.10
DNA technology was utilized during the research to sequence a patient’s genes. As a result, Bowcock and her colleagues discovered a rare CARD14 mutation in a large family with Northern European descent wherein plaque psoriasis was prevalent. This rare mutation did not only lead to plaque psoriasis, however, as the gene was detected in one-third of family members who were affected with psoriatic arthritis.11
However, the CARD14 gene mutation was revealed to not only occur among families with a genetic disposition. According to the researchers, a 3-year-old Haitian girl developed pustular psoriasis despite her parents not having the condition. This means that the CARD14 mutation occurred spontaneously and was not inherited.12
Other gene mutations were also discovered that may predispose a person to a type of psoriasis called pustular psoriasis, namely IL36RN and AP1S3. Both genes were identified by a team from King’s College London with Francesca Capon, Ph.D. at the helm.13
Capon, who was awarded a $50,000 NPF grant for this study, and her team also used gene sequencing technology to examine the DNA of nine individuals with pustular psoriasis. Once they narrowed the focus of their study to the AP1S3 gene, they analyzed it in another 100 patients. Ultimately, the team discovered AP1S3 gene mutations in 6 percent of patients. According to Capon:14
"It is not such a stretch of the imagination to think that if you have something wrong with that gene, there will be something wrong with your inflammatory responses."