Pyogenic arthritis, pyoderma gangrenosum and acne (PAPA) syndrome is a rare autoinflammatory bone disease, which caused by proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1) gene mutations.Due to a lack of awareness of it among clinicians, PAPA syndrome is hard to diagnose and easy to be misdiagnosed or miss-diagnosed clinically.In this paper, twin brothers with recurrent fever and joints pain were reported.They were diagnosed with suppurative arthritis by many hospitals, but after receiving the joint cavity incision operation with negative pressure drainage for several times and antibiotics treatment, their conditions were not improved.Genetic tests showed that the twin brothers had a heterozygous mutation p. E250K (NM003978.3; c.748 G>A; p.Glu250Lys) on the PSTPIP1 gene.They were finally diagnosed with PAPA syndrome and improved with glucocorticoid therapy.

In addition to the pyogenic arthritis, pyoderma gangrenosum and acne(PAPA) syndrome, autoinflammatory diseases caused by mutations in the proline-serine-threonine phosphatase interacting protein 1 (PSTPIP1) gene also include a group of clinical syndromes such as PSTPIP1-associated myeloid-related proteinemia inflammatory(PAMI) and pyoderma gangrenosum, acne, and hidradenitis suppurativa(PASH) syndrome.In this paper, the expanded spectrum and clinical characteristics of PSTPIP1 related autoinflammatory diseases were reviewed, so as to deepen clinicians′ understanding of this disease, facilitate early diagnosis, and finally improve the prognosis of patients.