Objective: To ascertain the occurrence and characteristics of uveitis in sibling pairs affected with juvenile idiopathic arthritis (JIA).
Methods: The sibling series comprised 80 JIA patients from 37 families with two or three JIA children, seen at the paediatric department of the Rheumatism Foundation Hospital in Heinola, Finland. An ophthalmologist examined the children for uveitis two to four times a year and the course of the condition was recorded during the follow-up.
Results: Uveitis was diagnosed in 21 of the 80 patients (26%). Three pairs (3.4 pairs expected) were concordant for the presence of asymptomatic uveitis. Two patients with enthesitis-related arthritis had acute unilateral uveitis. Among the remaining cases, uveitis was chronic and continuously active at the end of follow-up in 13 instances, but in spite of this only one patient had impaired vision. HLA allele B27 occurred more frequently in patients with uveitis than in those without uveitis (52 vs 30%, P=0.073) and all six subjects in the pairs concordant for chronic uveitis carried this allele.
Conclusions: The observed concordance rate for uveitis did not differ from that expected. Although the uveitis was chronic in most instances, its course was usually mild.