MVK and A20 haploinsufficiency: In the presence of a “true” and recurrent buccal and/or genital aphthosis, the following may be considered: idiopathic recurrent benign buccal aphthosis, inflammatory bowel disease (IBD), Mendelian autoinflammatory syndromes (HA20, mevalonate kinase deficiency MKD), and Behçet-like syndromes.