title: Distinct phenotype of early childhood inflammatory bowel disease.
abstract: OBJECTIVE
  Our goals were to answer 2 questions: (1) Is the presentation of early-onset inflammatory bowel disease (IBD) similar to typical adolescent-onset IBD? (2) Is there variability in familial aggregation in childhood IBD?
  
  
  BACKGROUND
  The phenotype of IBD in children under 5 years of age (early-onset) is poorly defined. Clinical and genetic studies of IBD, however, generally assume the phenotype to be homogenous throughout childhood.
  
  
  METHODS
  We analyzed data from 413 consecutive pediatric IBD outpatients attending our center between 1995 and 2000. Disease type, anatomic distribution, and family history were compared between children presenting before (early-onset) and after the age of five (5 to 15 y).
  
  
  RESULTS
  Disease presentation was predominantly colonic in early-onset IBD, most patients presenting with ulcerative colitis (UC). Isolated colonic disease was most frequent in early-onset Crohn disease (colonic 76.5%, ileocolic 24%) compared with ileocolic disease (ileocolic 45.5%, colonic 26%, ileal 19.4%, proximal 6.3%) in the older age group. First-degree family history was highest in early-onset UC 26% versus 11% in the older UC group.
  
  
  CONCLUSIONS
  We describe a distinct phenotype of early childhood onset IBD, with a strikingly high familial aggregation in UC and greater tendency to present with colonic disease. As more genetic heterogeneity is identified in IBD, careful definition of phenotype is required to identify further susceptibility genes. The early-onset form of UC presents an ideal group for further genetic analysis. These phenotype differences also suggest that treatment and outcome may vary in early-onset childhood IBD; prospective studies are required to confirm this.
authors.affiliation: Division of Pediatric Gastroenterology, Nutrition and Liver Disease, Hasbro Childrens Hospital, Brown Medical School, Providence, RI, USA. Thankam_Paul@brown.edu
authors.forename: Thankam
authors.initials: T
authors.lastname: Paul
authors.forename: Audrey
authors.initials: A
authors.lastname: Birnbaum
authors.forename: Deb K
authors.initials: DK
authors.lastname: Pal
authors.forename: Nanci
authors.initials: N
authors.lastname: Pittman
authors.forename: Clare
authors.initials: C
authors.lastname: Ceballos
authors.forename: Neal S
authors.initials: NS
authors.lastname: LeLeiko
authors.forename: Keith
authors.initials: K
authors.lastname: Benkov
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D002648:Child; D002675:Child, Preschool; D003093:Colitis, Ulcerative / Q000453:epidemiology / Q000235:genetics*; D003424:Crohn Disease / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010641:Phenotype; D012189:Retrospective Studies