Rheumatology (Oxford). 2006;45, 8:972-974.
Objectives. Juvenile idiopathic arthritis (JIA) is the commonest rheumatic disease
of childhood. Uveitis is the commonest eye complication of JIA, potentially leading
to eye surgery and/or visual loss. JIA is a complex genetic trait with well-established
HLA-DRB1 associations. The aim of this study was to investigate the involvement of
HLA-DRB1 in JIA-associated uveitis. Methods. A set of 130 UK Caucasian simplex families
consisting of healthy parent(s) and a child affected with juvenile oligoarticular
idiopathic arthritis (of which 31 had developed uveitis) had previously been screened
for multiple markers in the major histocompatibility complex region. Associations
with uveitis were investigated through haplotype pattern mining (HPM) and the extended
transmission disequilibrium test (ETDT). A further set of 228 UK Caucasian patients
with long-standing JIA were fully genotyped for HLA-DRB1 using PCR with sequence-specific
primers. Associations of HLA-DRB1 alleles in patients with uveitis (n=50) were examined
individually using the chi(2) test. Results. In the first cohort, HPM identified significant
associations of HLA-DRB1*13 with uveitis in juvenile oligoarthritis (P=0.002). The
ETDT confirmed overtransmission of this allele in the families (empirical global P=0.018).
In the second cohort, the significant association of uveitis with HLA-DRB1*13 was
replicated (P=0.0002, odds ratio 3.4, 95% confidence interval 1.7-6.5). Conclusions.
This study has established the HLA-DRB1*13 association with uveitis in JIA. Further
work is necessary in order to explore the prognostic potential of this marker.