Abstract: The patient 1, a 13-year-old boy, was admitted due to "recurrent oral ulcers for 3 years, abdominal pain for 8 months, and perianal ulcers for 10 days"; The patient 2, a 3-year-old boy, was admitted due to "recurrent abdominal pain, diarrhea, and fever for over 3 months". Genetic testing of both patients revealed "deficiency in ELF4, X-linked" (DEX), and the patients were diagnosed with Behcet's disease-like syndrome due to deficiency in ELF4, accordingly. The patient 1 was successively given intravenous methylprednisolone pulses and oral prednisone and mesalazine for symptomatic treatment. The patient 2 was successively treated with corticosteroids combined with enteral nutrition, as well as oral mercaptopurine. Subsequently, both patients showed improvements in symptoms and were discharged.