PSTPIP1-associated incomplete PAPA syndrome. Case report

PAPA syndrome (Pyogenic sterile arthritis, pyoderma gangrenosum, and acne syndrome) is a rare disease even among infrequent systemic autoinflammatory diseases. The disease is caused by mutations in the PSTPIP1 gene encoding the CD2 antigen binding protein 1, or proline-serine-threonine-phosphatase-interacting protein 1. Little is known about the function of PSTPIP1, presumably, the hyperphosphorylated mutant protein binds more strongly to pyrin, which leads to hyperproduction of interleukin-1. The aim of the study is to describe a clinical case of PAPA syndrome in a 35-year-old woman and to provide current understanding of this disease based on scientific publications. In the domestic literature, we did not find publications on the PAPA syndrome, confirmed by genetic analysis. In adolescence, the patient had arthritis, most often affecting the knee and wrist joints, at the age of 22, cracks appeared on the fingers, and from the age of 33, ulcers with undermined edges on the palms, fingers, and persistent acne on the face and back appeared. Other manifestations included gastrointestinal symptoms, general weakness, dizziness. Differential diagnostics with allergic, gastrointestinal, autoimmune, endocrine and dermatological diseases was carried out, mast cell activation syndrome was excluded. Whole exome sequencing revealed PSTPIP1_A230T mutation. The rarity and phenotypic heterogeneity associated with PAPA syndrome make diagnosis difficult especially in adult patients for physicians. Because most patients do not show the full spectrum of the classic triad, genetic testing is critical to diagnosis.