title: Juvenile idiopathic arthritis in multicase families.
abstract: OBJECTIVE
  To characterize juvenile idiopathic arthritis (JIA) patients from multicase families.
  
  
  METHODS
  The study series comprised 80 affected siblings belonging to 37 families. Comparisons were made with a population-based series of JIA patients from Finland and with a sibling series from the United States.
  
  
  RESULTS
  The distribution of cases according to onset type was similar in the sibling and population-based series. The age at diagnosis was significantly lower in the sibling series (4.8 years vs 7.4 years; p < 0.001). There was more intra-pair similarity in onset and course types in the United States series compared to the Finnish series and the proportion of girls was higher in the former.
  
  
  CONCLUSIONS
  The only significant difference between familial and sporadic cases with JIA is an earlier onset of disease in familial cases. There is no essential difference in clinical features of the disease between patients in the multicase and sporadic groups. Differences between the Finnish and US series may be due to selection bias in the latter.
authors.affiliation: Rheumatism Foundation Hospital, Heinola, Finland.
authors.forename: H M
authors.initials: HM
authors.lastname: Säilä
authors.forename: H A
authors.initials: HA
authors.lastname: Savolainen
authors.forename: K M
authors.initials: KM
authors.lastname: Kotaniemi
authors.forename: O A
authors.initials: OA
authors.lastname: Kaipiainen-Seppänen
authors.forename: M T
authors.initials: MT
authors.lastname: Leirisalo-Repo
authors.forename: K V
authors.initials: KV
authors.lastname: Aho
mesh_terms: D017668:Age of Onset; D001171:Arthritis, Juvenile / Q000453:epidemiology* / Q000235:genetics; D002648:Child; D005192:Family Health; D005260:Female; D005387:Finland / Q000453:epidemiology; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D015995:Prevalence; D014481:United States / Q000453:epidemiology