Abstract: Objective To explore the clinical characteristics of autoinflammatory diseases (AUIDs) in children with recurrent abdominal pain. Methods The clinical data of autoinflammatory disease in 2 children with recurrent abdominal pain were retrospectively analyzed and the relevant literatures were reviewed. Results Both patients presented with recurrent abdominal pain. Case 1 was a boy with the onset age of 6 . 5 years. The child had been diagnosed with appendicitis and still had recurrent abdominal pain after surgical resection. Conventional anti-infection treatment was not effective. Idiopathic chronic colitis and erosive gastritis were later diagnosed, and the onset of abdominal pain could be controlled with hormone therapy. Whole-exome sequencing (WES) was applied and a new heterozygous variation of the TNFAIP 3 gene was found in Case 1 . Thereafter, he was diagnosed with haploinsufficiency of A 20 (HA 20 ). Case 2 was a girl with the onset age of 2 years and 9 months. Her peripheral blood white blood cell count and C-reactive protein were elevated. She had received conventional antiinfection treatment in a local hospital for 5 months, but the effect was not satisfactory. The patient was subsequently diagnosed with autoimmune bowel disease, and recurrent abdominal pain occurred after oral treatment with prednisone. A heterozygous variation in the MEFV gene was found through WES, and she was diagnosed with familial Mediterranean fever (FMF). After searching in the databases, 11 articles and 45 cases ( 11 of HA 20 and 34 of FMF) were reported in China in patients younger than 18 years old. The median onset age of HA20 was 3.3 years and the median onset age of FMF was 5.7 years. About 25% patients presented with recurrent abdominal pain. Conclusions For children with long course of disease and recurrent abdominal pain accompanied by significantly increased inflammatory cytokines, autoinflammatory diseases should be considered. The gene testing and appropriate treatment should be provided.

Key words: autoinflammatory disease; haploinsufficiency of A 20 ; familial mediterranean fever; abdominal pain; child