Infantile Onset Intractable Inflammatory Bowel Disease Due To Novel Heterozygous Mutations In Tnfaip3 (A20)

Background: Mutations in tumor necrosis factor alpha-induced protein 3 (TNFAIP3), a key player in the negative feedback regulation of nuclear factor-kappa B signaling, have recently been recognized as leading to early onset autoinflammatory and autoimmune syndrome. Here, we have reported the phenotypes of 3 infantile onset intractable inflammatory bowel disease (IBD) patients with TNFAIP3 mutations and reviewed previously reported cases to establish phenotypic features associated with TNFAIP3 monogenicity.Methods: From January 1, 2015, to December 31, 2017, we recruited 58 infantile-onset IBD patients. Targeted sequencing and whole-exome sequencing were performed. Sanger sequencing confirmed the variants and determined the parental origin. We followed all the patients with TNFAIP3 mutations in our cohort and analyzed their clinical data.Results: Genetic screening in all 58 patients with infantile-onset IBD revealed 44 (75.9%) cases of monogenic disorders, and 3 de novo TNFAIP3 mutations were identified, including 1 nonsense and 2 frame shift mutations. All the mutations resulted in premature stop codon. All 3 patients had multiple systemic involvements, with predominant gastrointestinal diseases.Conclusions: Most infantile-onset IBD was associated with monogenetic mutation, and in addition to the 50 reported genes, other rare genetic variants need to be determined. TNFAIP3 may be an important candidate gene. The treatment of TNFAIP3-associated infantile-onset-IBD was challenging.