Diagnosis of Crohn's disease and other chronic enteropathies associated with prostaglandin deficiency

With the development balloon-assisted endoscopy and capsule endoscopy, the chance for encountering enteropathies of obscure origin has been increasing. There are various diseases, which should be considered as differential diagnoses of CD. The mucosal lesions in NSAIDs enteropathy occur predominantly in the ileum in multiplicity as circumscribed ulcers or tiny mucosal defects. Observational studies suggested that approximately 50% of subjects taking NSAIDs had mucosal lesions in the small bowel. There are other chronic enteropathies characterized by small bowel mucosal lesions. Cryptogenic multifocal ulcerous stenosing enteritis (CMUSE) is a disease initially reported from Western area in 1970s. Recently, CMUSE occurring in two siblings with an identical and homozygous 4bp deletion of cPLA2α has been reported. This observation suggests that CMUSE is a genetic disorder with PG deficiency. Chronic nonspecific multiple ulcers of the small intestine (CNSU) is another enteropathy reported from Japan. Exome analysis of patients with CNSU and an unaffected sibling revealed that the gene responsible for CNSU is SLCO2A1, which encodes a PG transporter. Based on these observations, there seems to be at least three types of enteropathy associated with PG deficiency, namely NSAIDs-induced enteropathy, an enteropathy associated with dysbiosynthesis of PG, and an enteropathy associated with disturbance in uptake of PG.