青壮年期に診断されるmonogenic IBD

Monogenic Inflammatory Bowel Disease Diagnosed in Adults

要旨●成人の炎症性腸疾患（IBD）の診断において考慮すべきmonogenic IBDとして，家族性地中海熱（FMF），非特異性多発性小腸潰瘍症（CEAS），XIAP欠損症，慢性肉芽腫症，A20ハプロ不全症などが挙げられる．FMFは多彩な内視鏡所見を呈し，潰瘍性大腸炎とCrohn病のいずれにおいても鑑別が問題となる．これに対し，CEASは小腸型Crohn病の診断において考慮すべき疾患である．一方，筆者らはCOL2A1バリアントによって発症する先天性脊椎骨端異形成症に合併したIBDU（inflammatory bowel disease unclassified）症例も経験している．このように，成人のIBD診療においてもmonogenic IBDの考え方は常に念頭に置くべきと考えられる．

　Monogenic IBD（inflammatory bowel disease）is a type of hereditary IBD that is induced by a specific variant of the responsible gene. This disease predominantly occurs in infants and children. However, there are diseases, such as familial Mediterranean fever, chronic enteropathy associated with SLCO2A1, XIAP deficiency, chronic granulomatosis, and A20 haploinsufficiency, which are diagnosed in adolescents and adults. Therefore, it is suggested that monogenic IBD should be considered a differential diagnosis in adult cases of unclassified IBD. Conversely, there are possibly hereditary disorders with intestinal inflammation that are yet to be categorized as monogenic IBD. Our experience suggests that the COL2A1 variant in type 2 collagen disorders may be an example.