Analysis of the Clinical and Genetic Characteristics of 3 Cases of A20 Haploinsufficiency

Abstract

Background To evaluate the clinical and genetic characteristics of 3 children with HA20. Methods The clinical and genetic testing data of 3 children with HA20 treated at CIP between August 2016 and October 2019 were retrospectively analysed. Results Patient 1 presented with arthritis and inflammatory bowel disease, patient 2 presented with axial spinal arthritis and lupus-like syndrome, and patient 3 presented with recurrent oral ulcers, gastrointestinal ulcers, and perianal abscesses. For laboratory examination, In patient 1, the WBC,CRP and AESR showed high. In patient 2, the WBC was normal, but CRP and AESR showed high. In patient 3, the WBC, CRP, and AESR showed high. Patient 2 was positive for antinuclear antibodies, anti-Sjögren’s syndrome antigen A, dsDNA, rheumatoid factor and Coombs test. Genetic testing showed that the 3 patients were heterozygous for mutations in the TNFAIP3 gene. For treatment, patient 1 used TNFα antagonist and thalidomide, patient 2 used TNFαantagonist and sulfasalazine, and patient 3 used hormones and thalidomide. Patients 1 and 2 were followed up for 4 and 3 months, respectively. There was improvement in joint and gastrointestinal symptoms, inflammatory indices and RF were normal, dsDNA and Coombs test became negative. Patient 3 was treated at an outside hospital and showed gradual improvement in oral ulcers and perianal abscesses. Conclusion HA20 is a single-gene auto-inflammatory disease caused by mutation in the TNFAIP3 gene. It presents clinically as a Behçet-like syndrome and can present as various other autoimmune diseases as well. Hormones and immunosuppressive agents are effective treatments, and cytokine antagonists can be used in refractory cases. Whole-exome genetic testing should be proactively performed for children with an early age of onset or Behçet-like presentation to achieve early diagnosis and accurate treatment.