Behcet’s　disease　developed　under　treatment　for　frequently　relapsing　nephrotic　syndrome．

Abstract

　It　is　extremely　rare　that　Behcet's　disease　arises　as　a　complication　of nephrotic　syndrome（NS）．　The　case described　herein　is　that　of　a　l3-year-old　boy．　NS　onset　occurred　at　six　years　old,　progressing　to　frequently relapsing　NS．　However，　mizoribin（MZR）high-dose　therapy　can　achieve　long-term　remission．　He　came　to repeat　erythema　and　stomatitis　from　MZR　high-dose　therapy．　Orthodontic　therapy　had　been　started．　He　was diagnosed　as　having　Behcet's　disease　taking　the　ocular　attack　as　an　opportunity　7　years　after　NS　development． Human　lymphocyte　antigen（HLA）typing　was　positive　for　HLA-B51． 　　　The　causes　of　Behcet’s　disease　and　NS　remain　unclear．　ln　this　case，　therapeutic　agents　including steroids　and　MZR，　as　well　as　HLA　and　oral　mucosal　irritation，　might　have　affected　Behcet's　disease　development． 　This　extremely　interesting　case　is　useful　to　elucidate　the　pathogenic　mechanism　of Behcet's　disease．