title: The influence of heredity for psoriasis on the ILAR classification of juvenile idiopathic arthritis.
abstract: OBJECTIVE
  To evaluate how heredity for psoriasis influences classification according to the International League of Associations for Rheumatology (ILAR). Heredity for psoriasis is currently both an exclusion and an inclusion criterion for different types of childhood arthritis according to ILAR classification criteria.
  
  
  METHODS
  Twenty physicians in 5 Nordic countries prospectively collected data from the incident cases in their catchment areas over an 18 month period beginning July 1, 1997. Clinical and serological data from the first year of disease were collected.
  
  
  RESULTS
  Of the 321 patients included who could be classified according to ILAR criteria for childhood arthritis, 50 (15.6%) patients were excluded from 55 classification events and fulfilled criteria for "other arthritis 1" i.e., did not fulfill criteria for any of the other classification categories, primarily because of heredity for psoriasis. If psoriasis in second degree relatives was disregarded as an exclusion criterion, only 8.7% of the patients remained in the "other arthritis 1" subgroup. For 20.6% of the whole group, heredity for psoriasis in a first or second degree relative (or both) and its distribution among arthritis subgroups did not differ except for juvenile psoriatic arthritis.
  
  
  CONCLUSIONS
  We suggest that second degree heredity for psoriasis be withdrawn as an exclusion criterion from the ILAR criteria.
authors.affiliation: Department of Pediatrics, Falun Hospital and Göteborg University, Göteborgm, Sweden. lillemor.bernston@falun.mail.telia.com
authors.forename: Lillemor
authors.initials: L
authors.lastname: Berntson
authors.forename: Anders
authors.initials: A
authors.lastname: Fasth
authors.forename: Boel
authors.initials: B
authors.lastname: Andersson-Gäre
authors.forename: Troels
authors.initials: T
authors.lastname: Herlin
authors.forename: Jon
authors.initials: J
authors.lastname: Kristinsson
authors.forename: Pekka
authors.initials: P
authors.lastname: Lahdenne
authors.forename: Gudmund
authors.initials: G
authors.lastname: Marhaug
authors.forename: Susan
authors.initials: S
authors.lastname: Nielsen
authors.forename: Pirkko
authors.initials: P
authors.lastname: Pelkonen
authors.forename: Marite
authors.initials: M
authors.lastname: Rygg
mesh_terms: D001171:Arthritis, Juvenile / Q000145:classification* / Q000235:genetics*; D015535:Arthritis, Psoriatic / Q000145:classification* / Q000235:genetics*; D002648:Child; D015331:Cohort Studies; D006801:Humans; D011446:Prospective Studies