TNF and Behcet disease: Children appear to manifest ‘full-blown’ disease slower than adults (Box 2), leading to delays in diagnosis.86,87 The typical hallmark features of paediatric BD are painful, recurrent, oropharyngeal, perianal and genital ulceration (Box 2).85,88 In an echo of the later diagnosis of monogenic Blau syndrome in cases previously thought to be ‘early-onset sarcoid’, a monogenic mimic of early-onset paediatric BD, haploinsufficiency of TNFα induced protein 3 (TNFα-IP3), has been described.89