From the NIH: Aphthous stomatitis is linked to mechanical injuries, iron and vitamin deficiencies, and certain HLA types.
D006680:HLA Antigens / Q000235:genetics*; D006801:Humans; D009061:Mouth Mucosa / Q000293:injuries*; D013281:Stomatitis, Aphthous / Q000209:etiology* / Q000235:genetics; D014806:Vitamin B 12 Deficiency / Q000150:complications*
D006680:HLA Antigens