E41 PAPA Syndrome: response to methotrexate in four members of the same family

Abstract

Abstract Introduction PAPA syndrome (Pyogenic Arthritis, Pyoderma gangrenosum and Acne) is a rare autosomal dominant disease that mainly affects the joints and skin. It is linked to a mutation of a gene of a protein named PSTPIP1 located on chromosome 15q. Arthritis is destructive, oligoarticular and predominantly affects large joints. It usually begins during childhood and not responsive to most treatments. The diagnosis is late and arises with infectious arthritis, given the destructive and pyogenic nature of arthritis and biological inflammatory syndrome. Aim We describe the cases of four members of the same family affected by PAPA syndrome who were treated empirically with long-term corticosteroids and then methotrexate to improve their joint involvement. Case reports We report the cases of 4 male patients belonging to the same large family (3 brothers and a first cousin), aged 28, 23, 21 and 15 years (patients 1–4, classified by age), affected by PAPA syndrome who presented with recurrent osteoarticular infections treated with antibiotics. They have no other conditions except vitiligo in patient 1 and Down syndrome in patient 3. Diagnosis was made in patient 1 based on joint and skin involvement. Other family members were subsequently called for diagnostic evaluation. A treatment combining methotrexate (10–15 mg/week) and corticosteroids (5 mg/day of prednisolone weaned and discontinued after 6–12 months of initiation) was associated with clinical and biological response in all patients with a decrease in pain, clinical and ultrasound improvement of synovitis and normalization of biological inflammatory markers in all four cases. Methotrexate was well tolerated and maintained as monotherapy, associated with on demand NSAIDs. The current average follow-up is 2.3 years. Conclusion Through our observations, we report a possible beneficial effect and good tolerance of methotrexate on joint involvement in PAPA syndrome. A more rigorous study (larger sample size, control arm) is necessary to validate this treatment.