Psoriasis is not caused by somatic mutations in skin cells

Evan Walker
Evan Walker TheMediTary.Com |
A psoriasis rash on a legShare on Pinterest
Psoriasis can produce dry, itchy skin rashes. Jelena Markovic/Stocksy
  • Scientists are still unraveling the underlying mechanisms involved in psoriasis.
  • Somatic mutations play a role in the development of cancer.
  • A group of researchers recently investigated their role in psoriasis.
  • They concluded that psoriasis is not caused by somatic mutations in skin cells.

Psoriasis is one of the most common skin conditions in the United States. Mediated by the immune system, it causes red, itchy plaques to form on the skin.

It is estimated to affect more than 7 million adults in the United States — that’s around 3% of the adult population.

Despite this prevalence and its significant impact on quality of life, many mysteries still surround the condition.

This is partly due to significant gaps in our knowledge regarding the cellular mechanisms that underpin it.

On the hunt for answers, researchers in a recent study in the journal Nature Genetics, investigated the potential role of somatic mutations in the genesis of psoriatic plaques.

Somatic mutations are alterations in DNA that happen after conception. They can occur in any cell type except sperm and egg.

These types of mutations, which are a normal part of aging, are due to errors during DNA repair, environmental factors, or stress.

Once a somatic mutation occurs, the cell continues to grow and divide as normal, creating a lineage of mutated cells. Sometimes, these mutations provide a competitive advantage. These so-called driver mutations help the cells colonize tissue, replacing Healthy cells over time.

As these cells grow in number, they have the potential to influence disease risk and progression as well as how an individual responds to treatment.

Because mutations in oncogenes or DNA repair mechanisms can help cancer cells proliferate, cancer researchers have studied these mutations in detail.

To investigate whether somatic mutations might be important, the researchers recruited 111 participants with psoriasis with ages from 18 to 88.

From these people, they took 1,182 punch biopsies. Next, they compared whole genome sequences of cells in psoriatic lesions with cells from nearby patches of healthy skin.

The most common mutations they identified were related to ultraviolet (UV) exposure. These were present even in participants who had not received phototherapy — a common intervention for people with psoriasis.

The second most common mutation was related to the use of psoralens, a drug that helps skin become more light sensitive before UV-A treatment. However, they also identified these mutations in people who had not used psoralens.

The study authors suggest that this might be because, prior to 1996, manufacturers added psorlanens to some sunscreens. Mutations caused by these creams may have persisted since then.

They said they found no other mutations related to other treatments, such as topical steroids. Similarly, they found no evidence that somatic mutations cause psoriasis.

They also reported that psoriasis doesn’t interfere with the way in which skin cells develop from stem cells.

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