title: Pediatric modification of the Montreal classification for inflammatory bowel disease: the Paris classification.
abstract: BACKGROUND
  Crohn's disease and ulcerative colitis are complex disorders with some shared and many unique predisposing genes. Accurate phenotype classification is essential in determining the utility of genotype-phenotype correlation. The Montreal Classification of IBD has several weaknesses with respect to classification of children. The dynamic features of pediatric disease phenotype (change in disease location and behavior over time, growth failure) are not sufficiently captured by the current Montreal Classification.
  
  
  METHODS
  Focusing on facilitating research in pediatric inflammatory bowel disease (IBD), and creating uniform standards for defining IBD phenotypes, an international group of pediatric IBD experts met in Paris, France to develop evidence-based consensus recommendations for a pediatric modification of the Montreal criteria.
  
  
  RESULTS
  Important modifications developed include classifying age at diagnosis as A1a (0 to <10 years), A1b (10 to <17 years), A2 (17 to 40 years), and A3 (>40 years), distinguishing disease above the distal ileum as L4a (proximal to ligament of Treitz) and L4b (ligament of Treitz to above distal ileum), allowing both stenosing and penetrating disease to be classified in the same patient (B2B3), denoting the presence of growth failure in the patient at any time as G(1) versus G(0) (never growth failure), adding E4 to denote extent of ulcerative colitis that is proximal to the hepatic flexure, and denoting ever severe ulcerative colitis during disease course by S1.
  
  
  CONCLUSIONS
  These modifications are termed the Paris Classification. By adhering to the Montreal framework, we have not jeopardized or altered the ability to use this classification for adult onset disease or by adult gastroenterologists.
authors.affiliation: Wolfson Medical Center, Tel Aviv University, Israel.
authors.forename: Arie
authors.initials: A
authors.lastname: Levine
authors.forename: Anne
authors.initials: A
authors.lastname: Griffiths
authors.forename: James
authors.initials: J
authors.lastname: Markowitz
authors.forename: David C
authors.initials: DC
authors.lastname: Wilson
authors.forename: Dan
authors.initials: D
authors.lastname: Turner
authors.forename: Richard K
authors.initials: RK
authors.lastname: Russell
authors.forename: John
authors.initials: J
authors.lastname: Fell
authors.forename: Frank M
authors.initials: FM
authors.lastname: Ruemmele
authors.forename: Thomas
authors.initials: T
authors.lastname: Walters
authors.forename: Mary
authors.initials: M
authors.lastname: Sherlock
authors.forename: Marla
authors.initials: M
authors.lastname: Dubinsky
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Hyams
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D003093:Colitis, Ulcerative / Q000145:classification / Q000473:pathology; D003424:Crohn Disease / Q000145:classification / Q000473:pathology; D018450:Disease Progression; D006801:Humans; D007223:Infant; D015212:Inflammatory Bowel Diseases / Q000145:classification* / Q000473:pathology; D012720:Severity of Illness Index; D055815:Young Adult