Psoriatic arthritis (PA) is a chronic disease characterized by damage to the skin and joints [4, 13, 26]. PA belongs to the group of seronegative spondyloarthritis. PA develops in about 10-30% of people, more often at the age of 30-50 years [6, 18].

The cause of PA is not fully understood. Along with the immune system, genetic factors play a certain role in the development of the disease [7, 14].